Just remove it and buff the classes effected by the removal

They could keep the mouse movement, but disable input from it when a skill is used or something like that so people can still use mouse movement, but not exploit this. It's unfair to those that need mouse movement to completely remove it with combat.

A lot of the mouse movement stuff takes as much practice, if not more, than it does to learn how to fight against it.
But removing it would either call for partial or even complete reworks for a bunch of classes/specs. Or those currently heavily using it (and especially those damn near relying on it to perform on the level they currently do) would be significantly weaker, if not dead in the water, compared to the rest of the roster that doesn't (have to) use it.

I'll take Berserker as an example because many people seem to find that the most egregious case ever since Succ got reworked for the nth time and became quite strong:
Lava Piercer without mouse movement is so slow and predictable you quite easily grab the Berserker out of his protected movement/engage before he gets to you to grab, or dodge out of his way if your class/spec has no grab. Predatory Hunt jump being another good (perhaps even better) example too with the "It's unfair that he teleports when he jumps" argument. Okay... but how is this different from Drakania, Lahn, (awk) Nova who also fly in from outside of render distance and appear next to you teleport style because of how fast they travel such vast distances? Or Striker jumps and flips desyncing all over the place making them untraceable? That's all fine, because it's without using mouse movement? Because the result is practically the same.

The game as a whole is riddled with desync and mouse movement is definitely a part of this, but only a fraction of the big picture. It's also more of a double edged sword as it takes (some) skill and practice to pull off so it's not just a free "cheat" everyone can reliably do right out of the gate without putting in at least a bit of effort to become decent to good at it. Like the classes that have skills reliably doing the same thing, but without mouse movement required. Don't get me wrong, I understand how it can feel unfair or unbalanced, but so are plenty of other things that don't involve mouse movement and each class has at least something that can make you feel that way, with or without mouse movement.
All this being said I don't think taking the feature away is the play. Especially with it resulting in a fair chunk of classes getting nerfed, and for some class' cases even forcing PA to rework them because of it, it's not the right call. Definitely not with plenty of other long existing things that'd be much higher priority when it comes to being in need of a fix.

to avoid confusion i was not trying to talk about ninja and berserker specificly, merely give examples by pointing out very common known abilities
i think your agruement of it not being a high priority fix is one that is debatable, looking at the state of current the AoS season

mouse movement in combat = skill is something i also get behind so do not get me wrong here but 
mouse movement in combat = inconvenience by just the same degree because there are alot of different ways to improve skill useage 

a grab should be predictable, because it is the ultimate form of CC in the game and should be punishable in response of being able to dodge it without any weird abrakadabra happening
a counter agruement such as "my class relies alot on grabs" is one i will simple not reply to because every class can kill without it, if it takes you one or two combos, a grab still gives you a massive advantage. but my post is not about grabs. 

it's about how unfair mouse movement is perceived on a receiver's end, if pearl abyss somehow manages to keep mouse movement and mitigate these problems, i am all for it but i just simple don't see this happening so i suggested different ways in order to fix it 
and i feel as a community we should speak up, regardless of how much of a priority people think this is or not 
it is a problem that should be fixed/removed after many many years.

 

"Learning" to use FG in reaction as opposed to proper spacing, or invulnerability to negate 360 degree grabs that would otherwise punish poor aim or reward good spacing, is not "tak[ing] as much practice, if not more, than it does to learn how to fight against it." That's just delusional to say, on the level of people who used to think release K'Sante was balanced - you're not good because you ignore the rules.

Really? The skill that's designed to be slow & predictable on the class with vast amounts of health and favorable class damage ratios in return for having slow & predictable skills is what it should be if you aren't abusing an engine exploit? Shocker. I don't know why you even brought this up, since Berserker's a perfect demonstration of why it's a problem and how brainless it is to turn Berserker into an assassin when nothing about their design or skillset suits that. Don't even bring Awa Drakania up, you're just digging the hole even deeper - she's only second to Berserker in how broken she is, and, what do you know, it's for all the same reasons.

Saying it takes skill is just a double-edged sword; you're either neutering the class for people who can't/don't want to click-to-move in an action RPG because it negates the weakness of making a bad move in a fight (thereby reducing skill expression, not increasing it) for the people who do abuse it, or you're wrong and it turns out it's very easy to do and effectively negates the weakness of classes for everyone. Now, I've seen plenty of Berserkers in Season Arsha doing it... so, uh...

Stop arguing that it'll result in classes getting nerfed. You're legit just stating, over and over again, that you won't be able to smash your face into your keyboard and win a fight because you abused mouse movement. Learn to play the game.

As for grabs, they're effectively a guaranteed OHK if you land them. They should be difficult to land. This magic bull[REDACTED] where people get to teleport right on top of you after cleanly missing a grab and land it anyway because they desynced it via mouse movement is the clowniest [REDACTED] I've ever seen in a game and creates a toxic atmosphere where you're supposed to be invulnerable 24/7 around any class with a grab. If you're in favor of it, that's because you're abusing it.

 i understand and can get behind your way of thinking