So the assumption is all based on your perception of time. It's already stated that a round is supposed to represent roughly 6 seconds. So, moving it a full 30 feet is only moving it 5 feet per second. With that expectation, it breaks your idea.

Quote from Kordis >>

Can this spell work as a conduit for touch spells like shocking grasp & vampiric touch?  Or is that strictly done through the wizard's familiar now?

 That could be an interesting house rule.  

Part of a reason why using a shield gives you +2 AC is that you can quickly reposition the shield to deal with incoming attacks. 

When you attack someone, you try to hit them in a weak spot, a place that's open to attack, 10% of the time that the 2AC from the shield makes a difference, it's likely because the user moved the shield to protect themselves - it's rarely because the attacker mindlessly put their sword swing into the shield. 

In addition, when you brace a shield against a weapon attack, you're usually bracing against significantly more than 10 pounds of force.

If you hold a shield up with a mage hand, it doesn't really function as well as "using a shield" - the mage hand can't quickly maneuver the shield to block attacks, and many damaging blows from weapons would just knock it aside and continue through to the person behind it. So I wouldn't say that a shield held by a mage hand has an appreciable impact on your AC.

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Think of it like this. If a shield was placed on a display stand, and you stood next to it, would you consider that to be worth 2AC? partial cover? - I think most DMs would rule no.

Because someone with perceived authority said so. 

Using the Reduce spell to get your character under 10 pounds, you could use Mage Hand to fly. Albeit, flight time would be limited to the duration of the "Reduce" spell.

As long as the character is less than 80lbs to start, you're golden.

Gnome, Halfling, Goblin, Kobold, and probably Fairy and Harengon and certain 'lineages' too. Probably even more options if the character happens to be lighter/adolescent.
Also consider Polymorphed characters or Druid Wild Shapes that have a very light weight.

Can the hand drop say a 10 pound item from a height of 30 feet? The 10 pound object would be traveling at almost 30 mph when it would hit. Could this be something that could be used to cause say bludgeoning damage?

Quote from GMO >>

Why would one not be able to accelerate a 1 pound object to lethal velocity with a mage hand?  By my calculations, 1 pound of the hand force would be holding up my 1 pound object, allowing 9lbs of force to act on the object or 9 x gravity.  Over 30', this would result in an 1 pound object moving roughly 94 MPH.  Or the energy in a 9mm bullet. And that assumes a straight line, one could spin the object around, until it reach max centripetal force (9x gravity), that would add an addition energy making the 1 pound object hit at 210 MPH or just under a 12 gauge shot gun round of energy.  

 This would classify as an attack, which the mage hand explicitly can't do.

I can move a 10 pound object 30 feet with my hand but i cant turn a 1 pound object into a bullet

would the hand be large?

Could you use this spell and have it accelerate your hand to said speed? If so, then you could throw a rock or coin or something at... Whatever speed moving 30 feet instantaneously is (or however long your arm is, whether you're using Transformation or not) ... Then you could bypass the rule stating it can't attack.

Sure, why not. But how accurate will the shot be if you habe to aim it from afar? A warning shot? Yes! A aimed shot? Have fun with disadvantage, no proficency bonus, and something like an additional -5 to hit. Also the Hand would have its own dex sooo yeah.

Mage Hand doesn't say you need to see it, but how would you be able to do something useful while not being able to see what it's doing?

Changed Control Fire to this, seems a lot more practical.

this spell is so good

Does anyone know if a Mage Hand has force feedback? In other words, if you wave it through a space that appears to be empty, but is occupied by something invisible, would the caster know if the hand had met an obstruction? In this case the Mage Hand is invisible, since it's gained through the Telekinetic Feat.

The hand can’t attack. It is a paciFIST.

Quote from dlsumme >>

For using Mage Hand to do something annoying at distance...  any character can use their action to "help" in combat by distracting an opponent within 5' of them.  With mage hand, it seems like you could do the same thing at distance.  Tugging on someone's clothes, or attempting to stick a spectral finger up someone's nose, or grabbing at a holy symbol or arcane focus - these things are certainly distracting.  You couldn't pull off the clothes, injure their nose, or take the holy symbol - but you could be distracting and annoying.

 

As far as trying to actually steal something from a conscious character...  the arcane trickster's improved version specifically talks about very limited ability to do this as an added feature of their mage hand (thus implying the base version can't do it).  There are a number of things which work on unattended objects but not on possessions (for example, fire bolt will ignite unattended objects)...  it would seem reasonable a mage hand could grab an unattended weapon or a piece of gear laying on the ground, but not one actively possessed.  Still, it would serve at a minimum as a great distraction (thus the "help" action at a distance).

Re: 'help' type actions with mage hand.  If distracting an enemy is something spelled out as the benefit of a level 13 unique subclass feat, it's probably something that can't be done without that feat.  

Just like you mentioned with the stealing section, that kind of behaviour is described by 'Versatile Trickster' the level 13 Arcane Trickster feat. If you could confer advantage in combat by doing this kind of thing at level 1 without being in that subclass, what's the point of the feat? It clearly exists because it's not something you can normally do. 

Quote from Llewinidas >>

Short answer "for game balance, thats too powerful for a cantrip".

Long answer, I kind of agree with you though allowing a mage hand to hit someone with as much damage as a 9mm round is obviously game breaking, if you can throw 'create fire' for 1d6 fire damage mage hand should at least be able to do the same with a thrown object and should at least be able to attempt to punch for unarmed damage...

Quote from GMO >>

Why would one not be able to accelerate a 1 pound object to lethal velocity with a mage hand?  By my calculations, 1 pound of the hand force would be holding up my 1 pound object, allowing 9lbs of force to act on the object or 9 x gravity.  Over 30', this would result in an 1 pound object moving roughly 94 MPH.  Or the energy in a 9mm bullet. And that assumes a straight line, one could spin the object around, until it reach max centripetal force (9x gravity), that would add an addition energy making the 1 pound object hit at 210 MPH or just under a 12 gauge shot gun round of energy.  

For balencing purposes, I would not allow the hand to do something like that.  Mage Hand is a cantrip, and it isn't even supposd to deal damage.  It allows you to manipulate objects from a distance.  You can use it to open a chest from a distance (in case that chest might be trapped), or you can disarm a trap at range (you are safe if you accidently set it off).  This can also help you reach objects that are out of reach.  Similar to minor illusion, phantasmal force, or prestidigitation, the only limit is your imagination (and the mechanical constraints).  

If I allowed players to attack with the hand, I would probably use the same rules as an unarmed strike, but using your spellcasting ability instead of Strength, and dealing force damage instead of bludgeoning.  This damage would be smaller than cantrips specifically designed for attacking, but mage hand gets its virtue by having a lot of potential utility.     

Can a spectral hand move through objects? Like if i wanted to sneak the hand into an area through the ground grab an item and drag the item across the roof and out of a room. Would that be possible?

No, that's an attack. The hand cannot do anything to attack. It is (unfortunately) quite the pacifist.