Positionals.

I think they're awful in almost every conceivable way. It's the #1 reason I play a tank, because it's basically a melee DPS that doesn't need to do positionals.

1) The netcode is complete garbage and makes positionals even worse than they should be.
2) The devs even recognize that they suck and half the time they just make it a full circle (i.e. everything is considered a positional) due to boss design.
3) It'd help get rid of an otherwise useless button (True North).
4) It'd raise the skill floor, something that the devs seem to want to do, but consistently struggle with.
5) Stifles encounter design

I really wanted to reply to a bunch of people about their dislikes of "parsers, FFLogs, a few other notions", but I am unfortunately short on time. Consider yourselves lucky!