I love the piano roll in fl studio, something that ableton, reason, and reaper made really frustrating to use. It needs more transformation tools though (like clone and replace rhythm on existing bars).
I find myself getting automation clip overload often in projects which makes it difficult to organize everything. Although I’ve since started opening multiple instances of fl and doing the detailed automation work in smaller projects and exporting that as audio. Simplifies the production process and makes looking at the whole project easier.