>>51368736They introduced the best bottom screen for multiplayer ever in XY, then removed it in ORAS onward.
They introduced the DexNav in ORAS which perfected the concept of Pokemon chaining and removed tedious RNG for catching specific pokemon again, then removed it in SM.
They introduced the ability to fly to specific route signs in ORAS, but removed this in SM.
They introduced Mega Evolution in Gen 6 but did not build upon it in Gen 7, and removed it in Gen 8.
Older example, in BW2 they added the ability to have balanced rematches against all the Gym Leaders and Champions from across the franchise up until that point, but never returned the Pokemon World Tournament in future titles.
A super recent example is in PLA, Pokemon move towards their targets and make contact when attacking with moves that would make contact, but do not do this anymore in SV. It's a very prevalent, self evident issue GF has, of innovating in good and bad ways each generation, and then removing most everything come the next gen instead of only what didn't work well.