I think you're overlooking just how much of the blame for this lays squarely in SE's hands and always has done.

Remember BCoB turn 5? One of our tanks for prog was on PS3. Twintania's dive-bomb markers routinely wouldn't load in time or at all on the PS3 version and the client latency for EU players back then meant she had absolutely no chance if she just reacted to us moving either. We had to have her on the phone to get the clear because the game client just wasn't up to the job.

There are plenty of more modern if less extreme cases of this to this day where SE's client is just plainly subpar and the explosion of QoL features seen in some of these mods are a result of that. The ridiculously small cooldown counters. Not being able to see buff and debuff durations in the party bar. Being able to save more than 5 way marks total. Shields showing up on your own HP bar as well as the party bars. AST being able to get the Heavensward Card control style back to save on hotkeys. The list goes on and on.

These are things that a game raking in 200 mill+ a year shouldn't be overlooking.