I think a very large portion of bugs are the result of this game's Animation Cooldowns. If an animation isn't completely rendered, the character sometimes gets stuck without being able to perform other skills. For example, if you get thrown up into the air (say with volcanic rune) at the same time as being knocked down by another ability (say destro staff), then your character might get stuck on the ground, just floating around because the animations never completed.

Zenimax instituted Animation Cooldowns as an alternative to Global Cooldowns found in other MMO's.

However, I think the implementation of these Animation Cooldowns is what's causing a large portion of UI delay, buggy responsiveness and general unplayability associated to the game.

My recommendation would be the following:

1) Rework the animations for all abilities, and allow them to be scaled (i.e. less frames) so that they can be performed faster (if say, buffed under haste) or slower (if say weapon speed debuffed). This would allow flexibility and consistency.

2) Most animations in the game would need to be shortened to make a more playable and responsive game.

3) Require that the ability associated to the animation doesn't "cast" until the animation completes (i.e. the "casting time")

4) Remove animation weaving by not allowing abilities to interrupt yet still cast. This would also remove casting from under Block. You can still interrupt your own casts, but doing so means it doesn't cast.

I was playing a few other MMOs and looking at how smoothly the game was able to transition animations and ESO was very unresponsive by comparison. I really think that's the culprit for a lot of problems we're currently experiencing.