If a thing is prescribed or forbidden, then that is how I try to run it. If I don't like it, then I try to change the wording so that I do like it.

Sleep requires a creature use an action to shake or slap the sleeper awake (skirted if you can cause damage somehow without using an action, which a lot of things can). Mage Hand doesn't have anything that lets you manipulate a creature directly- as far as I can tell, you can't mage hand your hair into place, but you can mage hand a comb to comb your hair into place. It's pretty clear you could use an action with it to manipulate an item to wake up a sleeper, so long as you meet the conditions of sleep- for instance, sleep requires you use your action to shake or slap a creature awake. Mage hand can manipulate a glove using an action, and a glove can shake or slap. There's also things that skirt it a bit that I'd definitely count as allowed- for instance, pouring a flask of water on a sleeping creature is arguably slapping them awake, or something. It still costs the same action, after all.

Mage hand can't carry an object weighing more than 10 pounds, but that's not the same as being able to apply 10 pounds of force to a creature. Nothing in mage hand allows it to apply even a single tiny amount of force to a creature. Nothing in sleep allows you to get woken without costing an ally an action or costing you at least one hit point. I think I'm fine with all these restrictions but if you don't like them, propose some wording change that we could play with- I'm always happy to reprint a page to make a spell work better, after all.

As another note, mage hand can never be used to make an attack, but as it can explicitly manipulate objects in ways that could be harmful to an enemy- pouring poison from a vial was brought up- I guess that makes a saving throw the mechanism to avoid that.

In addition to mage hand being able to use a glove to slap someone awake as a bonus action now, I dug further into the potion thing. The short version is:
-I added a line to my houserules document (diffs) stating that potion use never counts as 'using a magic item'. There's nothing in the rules that states that pouring a potion is that type of action, but that should clear up any ambiguity.
-In addition to pouring a potion down a knocked out ally's throat, you can use that bonus action to pour it into your own mouth, or a willing ally's mouth.

Of course you still have to get the item you have to the mage hand, which would normally be an object interaction (you get one for free each round) that uses your hand (you can't do it while dual wielding, you'd have to drop a weapon first).

Further, I'll note that the text of Mage Hand Legerdemain lets you control the mage hand with your bonus action. It doesn't take away your ability to control it with an action, so if you wanted to control it twice in a round, you could. For instance, a fallen ally has a healing potion on his belt- your bonus action lets it go over to him and grab the potion, and your action could then give it to him.