I made a wizard subclass that focuses more on the natural world. However, I wasn't enthused about the first version and created a second one that dealt more with experimentation. 

School of Philosophy

Expert in Your Field
You are proficient in Nature. When you make a Persuasion check you can use your Intelligence modifier instead of your Charisma modifier.
You also gain an extra benefit based on your field of research.
Astronomy. You gain darkvision out to a range of 60 feet. If you already have darkvision from your race, its range increases by 30 feet.
Botany. You are proficient in Herbalism kit. You can also read, write, and speak Druidic.
Geology. You know the mold earth cantrip. If you already know mold earth you can choose another wizard cantrip.
Medicine. You are proficient in Medicine. In addition, you can use your intelligence modifier instead of your wisdom modifier for Medicine checks.
Meteorology. You know the shape water cantrip. If you already know shape water you can choose another wizard cantrip.
Zoology. You are proficient in Animal Handling. In addition, you can use your intelligence modifier instead of your wisdom modifier for Animal Handling checks.

Experimenter
At 6th level, once per turn when you cast a spell by expending a spell slot, you can expend another spell slot one level lower (minimum of 1st level) to create an Experimental Method. Experimentation can cause problems. When you use this feature, make an Intelligence check with a DC of 10 + spell slot of the spell.
If you succeed on the saving throw, the spell and the Experimental Method work as described. If you fail, the intended effect does not occur, instead a consequence described in the following Experimental Methods occurs.

Embolden. Add 1d4 to spell save DC. If you fail, creatures gain a +1 against the saving throw. At 14th level the DC increases by 1d6. On a failed check, creatures gain a +3 against the saving throw.
Endure. The duration extends to be 1d4 times as long. If you fail, the spell goes off 1d10 rounds after you finish casting the spell. At 14th level, the duration is 1d6 times the original duration.
Remote. You can increase the range by 1d4x10 feet. If you fail, the spell goes off at a random point in the new range. At 14th level the range is increased by 2d4x10 feet. Going from self to touch and from touch to 5 feet are each worth 5 feet.
Surge. Deal 2d10 more damage. If you fail, you deal 1d10 force damage to yourself. At 14th level, you deal 4d10 more damage. On a failed check, you deal 2d10 force damage to yourself.
Warp. If a spell deals acid, cold, fire, lightning, or thunder damage, you can substitute that damage type for another one from that list. If you fail the check, you deal half damage of the original damage type. At 14th level you also deal 1d10 more damage. On a failed check you deal half the damage of the original type and you are also dealt half the damage of the original type.
Withstand. You give 2d6 temporary hit points to a creature within range of the spell. If you fail the check, you deal 1d6 necrotic damage to that target. At 14th level, you give 4d6. On a failed check, you deal 2d6.

Mastery of Your Field
At 10th level, based off of your field of research, you gain one of the following features.
Astronomy. As an action, you can change the sky in a 1 mile radius of you. Astronomical bodies may appear, disappear, or move, the color of the sky can change. The light does not change.
Botany. As an action you learn the following things about the plant life in a 1 mile radius of you. The prevalence of certain plants, the location of a plant, and the terrain of the area.
Geology. You can burrow through nonmagical, unworked earth and stone. While doing so, you don't disturb the material you moves through.
Medicine. As an action, you can choose creatures up to your Intelligence modifier and suppress one of the following conditions for 10 minutes. Blinded, deafened, paralyzed, or poisoned.
Meteorology. If it is raining or windy, you can use your action to make it stop raining or choose the direction the wind blows in a 100-foot-radius sphere centered on you. This effect lasts until the start of your next turn.
Zoology. You can use your action to understand beasts for the next ten minutes. The knowledge and awareness of many beasts is limited by their intelligence, but at minimum, beasts can give you information about nearby locations and monsters, including whatever they can perceive or have perceived within the past day. While this effect is going, you can use your action to charm a beast within 20 feet of you. The beast must succeed on a Wisdom saving throw or be charmed by you and creatures you designate until this effect ends. If you or another creature you designated attacks the beast, the beast is no longer charmed and is hostile towards you.

Controlled Experiments
At 14th level you are considered proficient in Experimenter checks. Pick one of the Experimental Methods. When you cast a spell and apply that effect, you can choose to automatically succeed and replace every dice roll with a 2.

 My questions are Which version would you rather play? Which Experimental Methods could be considered Greater Experimental Methods? Are there too many different fields of study? How can I improve Master of Your Field?

I've tweaked the subclass and tried to include the best of both worlds.

School of Philosophy

Expert in Your Field

You are proficient in Nature. When you make a Persuasion check you can use your Intelligence modifier instead of your Charisma modifier.

You choose a field of study and you gain an extra benefit based off of this choice.

Astronomy. You gain darkvision out to a range of 60 feet. If you already have darkvision from your race, its range increases by 30 feet.

Biology. You are proficient in Animal Handling and Herbalism Kits. You can also read, write, and speak Druidic.

Geology. You know the Mold Earth cantrip. If you already know Mold Earth you can choose another wizard cantrip.

Medicine. You are proficient in Medicine. In addition, you can use your intelligence modifier instead of your wisdom modifier for Medicine checks.

Experimenter

At 6th level, once per turn when you cast a spell by expending a spell slot, you can expend another spell slot of a lower level to create an Experimental Method. Experimentation can cause problems. When you use this feature, make an Intelligence check with a DC of 10 + spell slot of the spell.

If you succeed on the saving throw, the spell and the Experimental Method work as described. If you fail, the intended effect does not occur, instead a consequence described in the following Experimental Methods occurs. You can use this feature a number of times equal to your Intelligence modifier per long rest.

Endure. The duration extends to be 1d4 times as long. If you fail, the spell goes off 1d10 rounds after you finish casting the spell. At 14th level, the duration is 1d6 times the original duration.

Remote. You can increase the range by 1d4x10 feet. If you fail, the spell goes off at a random point in the new range. At 14th level the range is increased by 2d4x10 feet. Going from self to touch and from touch to 5 feet are each worth 5 feet.

Surge. Deal 2d10 more damage. If you fail, you deal 1d10 force damage to yourself. At 14th level, you deal 4d10 more damage. On a failed check, you deal 2d10 force damage to yourself.

Quicken. You can cast a spell that has a casting time of an action as a bonus action. If you fail the check, you cast the spell as an action and can not take any bonus actions that turn. At 14th level, you cast a spell that has a casting time of one minute in a round. On a failed check, you can’t concentrate on any spell this round and you can’t take any action on your next turn.

Warp. If a spell deals acid, cold, fire, lightning, or thunder damage, you can substitute that damage type for another one from that list. If you fail the check, you deal half damage of the original damage type. At 14th level you also deal 1d10 more damage. On a failed check you deal half the damage of the original type and you are also dealt half the damage of the original type.

Withstand. You give 2d6 temporary hit points to a creature within range of the spell. If you fail the check, you deal 1d6 necrotic damage to that target. At 14th level, you give 4d6. On a failed check, you deal 2d6.

Mastery of Your Field

At 10th level, based off of your field of study, you gain one of the following features.

Astronomy. As an action, you can change the sky in a 1 mile radius of you. Astronomical bodies may appear, disappear, or move, the color of the sky can change. The light does not change. These changes last for ten minutes or until you remove them with a bonus action.

Biology. As an action, you learn the prevalent plants and animals, the location of a plant or animal and the terrain within a 1 mile radius of you.

Geology. You can move through nonmagical, unworked earth and stone. While doing so, you don't disturb the material you moves through. If you end your turn in earth or stone, you take 2d8 bludgeoning damage and are expelled to the nearest unoccupied space.

Medicine. As an action, you can sense and identify poison and disease within 60 feet of you for ten minutes. During these ten minutes, as an action you can choose a creature within 5 feet of you and either end one disease or the poisoned condition afflicting that creature.

Controlled Experiment

At 14th level, you gain access to Greater Experimental Methods. To apply a Greater Experimental Method you must expend a spell slot one level lower than than the spell slot used to cast the original spell. You can apply a Greater Experimental Method once per short rest.

Embolden. Add 1d6 to your spell save DC for this spell. If you fail, creatures gain a +3 on the saving throw.

Enlarged. The affected area is doubled. If you fail the check, the area is halved to a minimum of 5 feet.

Fastened. Dispel magic and counterspell do not automatic dispel the spell you cast, no matter what the level is. You can add 1d6 to the DC to counter or dispel the spell. If you fail, those casting counterspell and dispel magic against your spell roll with advantage.

Greater Warp. If a spell deals force, necrotic, radiant, or psychic damage, you can substitute that damage type for another one from that list. If you fail the check, you deal half damage of the original damage type.

Limited. You can choose 1d6 creatures. The chosen creatures automatically succeed on their saving throws against the spell, and they take no damage if they would normally take half damage on a successful save.

Theorem

At 14th level you are considered proficient in Experimenter checks. Pick one of the Experimental Methods. When you cast a spell and apply that method, you can choose to automatically succeed and replace every dice roll with the average roll.

New questions this time: Are there too many Experimental Methods? What other fields of study should there be? Is anything too overpowered?

Edit: Another question: What is a better name for this subclass?