Lmao the thought of a rogue yoinking a wizards component pouch and neutering a difficult encounter is so good it would be allowed at my table! But only once....

Makes me think of the fights in Mistborn. And even the gunfights in the Wax and Wayne series.

Where the combat exists but is also a distraction for using Allomancer skills to grab, steal or sneak things.

Since you use it a lot, I think it's worth telling you it's "sleight" of hand. Slight of hand would mean you have small hands like a certain political grifter.

"Sleight" and "feint" (which is basically sleight of hands for sports, you're using similar misdirection and speed) are both spelled "ei," which makes them good mnemonics for each other.

I was playing in a PF1e game where me and a friend got mind whammied and were told to disable/stop our allies in the best way we could. My character was a human Occultist that I had built to be great at Sleight of Hand, Steal maneuvers, and Disarm Maneuvers. So I snuck up on the party's full caster and stole his component pouch (forcing the player to go through his prepared list and find which spells he could even still cast), and disarmed the archer and chucked his bow up the side of a building (since he was a snake-man with a tail instead of legs, and climbing was pretty much out of the question)

Well, the basis of it is semi realistic, so I sure as hell wouldn't object to it as DM. It's the rules working just like they're supposed to, imo.

There is a functional, real world difference between disarming someone and pickpocketing them during a physical encounter. You couldn't use sleight of hand to disarm anyone, ever, because the thing is in their hand. Just like you can't disarm something out of a pocket.

But there's no reason you couldn't take someone's sword off their hip. Ever see those tethers cops use? Well, used to use. They use holsters that make it harder to snatch them now. Point being that a weapon that isn't in your hand is vulnerable to sneaky grabs, or even non sneaky ones from a skilled attacker.

A pouch of components, that's no different than a coin purse unless someone takes steps to make it so.

Here's the thing though. Not all targets are equally difficult. Someone sees you coming, and you're an enemy, they aren't going to just stand there. The act of moving into their space changes it a good bit. If they're also skilled in a similar way, i.e. having levels of rogue, they'll recognize what you're trying. A fighter isn't going to keep a dagger just loosely hanging at hip, and let you reach for it. You might have to grapple first, then make the grab. Or maybe a touch attack equivalent. It isn't the same as lifting a coin purse in a crowd, there's a higher level of difficulty involved.

Admittedly, with a 19 roll, you should have succeeded anyway, once any other criteria were met.

But, yeah, in principle, that's a totally valid idea. But it's also relatively easy to counter, and it isn't even unusual. If a component pouch is on a belt and firmly attached, that isn't sleight of hand any more. Auto fail to try and grab the pouch and run. You could empty the pouch, but not take the whole thing. You could maybe call it a sunder attempt, but that's still different.

A 20 foot dash is maybe three seconds, four from a dead stop. While you can get to someone before they can draw a weapon and hit you with it, it's still a lot of telegraphing to overcome. An experienced thug is expecting trouble, and would have some variety of unarmed combat in their kit, so it wouldn't be exactly as you described it, if the DM is thinking a little. But it's within believability.

An Arcane Trickster has invisible Mage Hand, so they can yoink pretty effectively.

Not a big deal, but FYI it's "sleight"

https://en.wikipedia.org/wiki/Sleight_of_hand

I pretty much did that last time I played, gank the wizard scrolls

I have largely the same opinion as the accepted answer on this RPG Stackexchange post.

That is, while the enemy is paying attention to you, you are not stealthed, you would not be able to sneakily snatch a pouch or unused weapons. But you can try to cut the straps holding them.

Personally, I would probably rule it like this:

If you actually try to go close in and grab a pouch and hold it in your hands, then after the Sleight of Hand check they get an opportunity attack on you, because you are focused on trying to snatch an object. They notice that opening to strike. And it would use their reaction. But again, this is my personal opinion.