Basically, right now when you are for example doing chains basic attack (holding left click), it gets extremely finicky throwing in an attack skill or spell in between your basic attacks. I am not sure what the game is doing right now there, but it definitely knows no concept of priority, which I propose as follows:

Each ability, spell, and basic attacks, are given a priority value. Any ability of a higher priority will take precedence and interrupt any of a lower one. In the aforementioned scenario, any active ability would interrupt any basic attack (the attack chain will resume once the interrupting ability animation has concluded, so you can keep that left button down through the whole thing).

• Priority 0: Lowest priority, gets interrupted by anything else. Only basic attacks fall into this category.
• Priority 1: Regular damage dealing abilities.
• Priority 2: CC abilities. Anything that stuns, slows, freezes, knockbacks etc. Only abilities that guarantee these effects are included here, if something just hassome freeze chance due to ailment status chance, it will still count as priority 1. However, if you can attach a guaranteed CC effect to a priority 1 ability through any means, it becomes upgraded to priority 2.
• Priority 3: Movement abilities. For example, Aether Jump, Evasion, and the regular stamina-based dodge.
• Priority 4: Defensive abilities. Abilities like Bulwark of Dawn, Duskshroud, and Juggernaut. Also includes all potions (healing and otherwise).