>>39044157XY = Not as good as it could been, but the Dex is great and it could be fixed with a third version cutting down on the handholding and OP giftmons, Online functionality is great as is Super Training for casuals, they gave the wrong Mons Megas.
ORAS = Gen 3+XY, DexNav was neat but other and the good XY online then that it is arguably a from Emerald.
SM: Cutscene Garbage, best part is probably the idea of 1-on-2 "bossfights" with the Totems, but they can't carry the game.
USUM: Ultra Cutscene Garbage, New Mons mid generation to try to force purchase of superflous games edition.
Gimmicks:
Megas issue is that they plop em on you as gifts and gave way too many mons that didn't need them the functionality, Shit like Mega Beedrill needs a Mega, Salamence, Mewtwo, Groudon,Kyogre and FUG does not.
Z-Moves are mixed bag, i liked the addition iof shit like Z-Conversion and Z-Parting shot giving new tactics to underutilized moves, but i really don't care for the standard and boring "200 BP Wallbreaker with cool animation" usage.