Only played ORAS, figuring I would get most of XY's goodies with most of Hoenn's good points in one package. XY didn't interest me at the time and I need only play Sun and Moon's demo to see what it was doing to the pacing. It has a lot of great little things and does address a lot of RSE's issues, as
>>39295325 says, brought down by a few big ones, and that and the corner cutting in a remake definitely turned me off to the rest.
It's funny, when I saw the scope of X and Y I was hoping Game Freak would use the smaller Pokemon count to focus on mechanics instead, and by head count the 3DS games actually did quite a lot there- Player Search System, character customization, Amie, Super Training, ORAS Secret Bases, Poke Pelago, etc.- but the games being generally easy, even more guided than before, and having only a Battle Tower to throw your best Pokemon at brought some of those great things down. I have yet to play any 3DS overhauls, though I have Dio and Dryano's for OR on hand, but they sound particularly juicy for giving you a chance to put all of that stuff to use.