Wild Magic is one of the original subclass from PHB. Which means it's very outdate mechanically and offers little to none for the team compare to other sorcerer's subclasses. It is a subclass that is infamously known for its friendly fire and negative impact on their team (fireball on self at 1st level). So I update these mechanics and rework some to give more control to the player of Wild Magic Sorcerer. And also provide them the support and utility for their team.

Disclaimer: I draw most of my inspiration and mechanic from other well-known or much much more experienced DM and players, not all of this is my design.

What changes did I make:

1. Incease the chance of triggering Wild Magic Surge but also give the Wild Magic Sorcerer more control. We all heard a story of wild magic gone wrong and TPK the whole team. So I give a Tide of Chaos feature to not only be able to give you an advantage on an attack roll, an ability check, or a saving throw but also Wild Magic Surge's roll.
2. Reduce the cost of Bend Luck but also give an option to pay more to gain more. 2 sorcery points for 1d4 change is not as good as the price, so I give an option for the player to choose between 1-3 sorcery point(s). Each point will again additional 1d4, which means 3 sorcery points can give 3d4 as bonus or penalty to an ally or an enemy. Making your presense beneficial to the team.
3. Give an option for players to use an action to trigger Wild Magic Surge. Want to play with some chaotic good time but doesn't want to spend a spell slot? This give you an option for some amazing role play opportunity and shenanigan. Also this could prove useful in combat when you're out of spell slot.
4. Tides of Chaos is now a team support feature. You can now use this feature to give your teammate advantage or your enemy disadvantage on their attack roll, ability check, or saving throw. You have the opportunity to be one of the lucky charm of the group and your teammate will love you for it.
5. Chaos Spell Lists. Sorcerer is one of those subclass which has little spell known. "Number of spell known = 1 + your sorcerer level" limits your ability to be a utility or a specialist to the team. Which is why I give some additional chaotic flavor spell, these spells counts as a sorcerer spell for you, but it doesn’t count against the number of sorcerer spells you know.
6. Spell Bombardment finally BOMB. As name suggest, your spell should be more explosive. But the mechanic falls short, one additionaly die is not worth being a 17th level class feature. So I give it a damage increase, unique to the chaotic nature of wild magic and worthy of end game 20th level combat.

Wild Magic Surge

Starting when you choose this origin at 1st level, your spellcasting can unleash surges of untamed magic. Once per turn, you can roll a d8 immediately after you cast a sorcerer spell of 1st level or higher. If you roll a 5 or higher, roll on the Wild Magic Surge table (or any variant version of Wild Magic table that your DM allows) to create a magical effect. If that effect is a spell, it is too wild to be affected by your Metamagic, and if it normally requires concentration, it doesn’t require concentration in this case; the spell lasts for its full duration.

Once you release the surge, the chance of releasing another surge is reduced. Now you consult the Wild Magic Surge table on a roll or 6 or higher. And so on until you consult the Wild Magic table only if you roll an 8.

Once you complete a long rest, the chance of producing a wild magic surge is reset to 5 or higher.

Additionally, once per turn, you can use an action to focus on the chaos power that reside within you. You trigger Wild Magic Surge with that action. You can use this feature a number of times equal to your Charisma modifier, and you regain all expended uses when you finish a long rest.

Tides of Chaos

Starting at 1st level, you can manipulate the forces of chance and chaos to gain advantage on one attack roll, ability check, saving throw, or Wild Magic Surge. Once you do so, roll a d8. If your roll is not 5 or higher you must finish a short or long rest before you can use this feature again.

You can also use this feature to give advantage on one of your ally's attack roll, ability check, or saving throw. An ally must be within 60 ft and you must have a line of sight. You can use this feature a number of times equal to your proficiency bonus.

Additionally, after Wild Magic Surge has triggered. You regain the use of this feature.

At 6th level, you can also use this feature to give disadvantage on one of an enemy's attack roll, ability check, or saving throw. An enemy must be within 60 ft and you must have a line of sight. You can use this feature a number of times equal to your proficiency bonus. This share the total number of time with give advantage to your ally feature.

Chaos Spells

You learn additional spells when you reach certain levels in this class, as shown on the Chaos Spells table. Each of these spells counts as a sorcerer spell for you, but it doesn’t count against the number of sorcerer spells you know.

Whenever you gain a sorcerer level, you can replace one spell you gained from this feature with another spell of the same level. The new spell must be an Evocation or a Transmutation spell from the sorcerer, warlock, or wizard spell list.

Chaos Spells

• 1st Level : Faerie Fire, Sleep
• 3rd Level : Blur, Misty Step
• 5th Level : Counterspell, Fireball
• 7th Level : Dimension Door, Wall of Fire
• 9th Level : Cone of Cold, Dream
• 11th Level : Harm, Heal
• 13th Level : Resurrection, Teleport
• 15th Level : Earthquake, Maze
• 17th Level : Meteor Swarm

 

Bend Luck

Starting at 6th level, you have the ability to twist fate using your wild magic. When another creature you can see makes an attack roll, an ability check, or a saving throw, you can use your reaction and spend 1-3 sorcery point(s) to roll 1d4 per a sorcery point you spend and apply the number rolled as a bonus or penalty (your choice) to the creature’s roll. You can do so after the creature rolls but before any effects of the roll occur.

Controlled Chaos

At 14th level, you gain a modicum of control over the surges of your wild magic. Whenever you roll on the Wild Magic Surge table, you can roll twice and use either number.  If you use Tides of Chaos feature with Wild Magic Surge, you may roll thrice and use one of the effect instead.

Spell Bombardment

Beginning at 18th level, the harmful energy of your spells becomes unstable. When you roll damage for a spell and it triggers a wild magic effect, roll the damage dice again and add to the original result.

For example, a Wild Magic Sorcerer of 18th level casts Fireball. They roll 25 for damage. They then roll to see if a wild magic surge happens and they roll an 8 and a wild magic effect occurs. In addition to the wild magic effect, they roll the damage dice again and roll a 28. Added to the original result the fireball now inflicts 53 points of damage in addition to the wild magic surge effect.

Once a number of spells have benefited from Spell Bombardment equal to your Charisma modifier, no additional spells are enhanced this way until you complete a long rest.