I think more then anything I just want healing to be less of a flowchart with more randomly distributed damage/dispellable debuffs you have to actually react to instead of just seeing the mechanic/cast bar, popping your cooldowns, then calling it a day.

Making boss auto-attacks non-trivial and consistently active during mechanics would also further put stress on both the healer and tank alike. There's just way too many breaks where you're at the leisure to top everyone off and/or pre-shield before the next instance of damage occurs.