Will 3.0 bring any much needed improvements to instant abilities?

Developers have remained very silent about the netcode issues that have plagued FFXIV since ARR launche.

Will we see any improvements to instant abilities in 3.0, i.e. truly instant abilities?

I don't know what the hallowed ground are you talking about.

Must be talking about the fact that there's a slight -but noticeable- delay between a given instant skill being selected, and when it actually gets executed (see: Benediction, Hallowed Ground, etc.).

Otherwise, we don't know. They haven't really talked about what fixes they're gonna introduce for the expansion proper (nor any brand new skills for older classes/jobs for that matter).

I'd love it. When a manawall/ward doesn't go off the instant I press it, my heart dies (and so does my character most of the time). Then again, I understand that the effect happens after the animation. Also, the enemies queue up damage, which is also some of the issues.

I'm pretty sure the delay to abilities has nothing to do with netcode. The ability doesn't activate until the animation is complete, that is all. It's more noticeable on 'I'm going to die' abilities like Hallowed Ground because of the result when it doesn't activate in time, but the delay exists for 'all' things.

Healing doesn't apply until the animation goes off. Threat/damage doesn't apply from Rage of Halone until after the third swing is complete. And on and on.

So no, I wouldn't expect anything to change.