>gen 1
gamewise, is a disaster. people only like it for nostalgia
>gen 2
still have a bad game curve, but is an improvement from gen 1. also, one of the best post games
>gen 3
RS were a nice improvement with a fantastic OST and Emerald was peak of the generation, probably one of the best games of the franchise. FRLG were a great surprise and nostalgia bait, but still worth playing.
>gen 4
DP felt like they got a bit lost with the ds capacity. the only redeeming thing were a couple of characters (cynthia, barry, cyrus) and some new evolutions. Platinum was a great evolution tho. HGSS was amazing but it could have been better if it corrected some of the gen 2 mistakes.
>gen 5
the peak of the DS era, in my opinion. BW have its issues, but this time felt like they really used the DS engine to the maximum. having a complete new dex was really refreshing. BW2 does have a couple of improvements, but I feel like it doesn't shine as much as BW. PWT was fantastic, tho.
>gen 6
I haven't played XY that much, but the game felt a bit underwhelming, just like what happened in gen 4. the OST wasn't that great, region was really nice, but it could have been way better. ORAS felt really nostalgic, and the OST was incredible, but the game lacked those tiny details from Emerald that were necessary to make a good gameplay
>gen 7
Alola is currently my favorite region because its different from everything we have seen. SM had a lot of problems, but it also introduced many features that are definitely here to stay like no more HM, title defense, more mini game challenges. USUM had some improvements, and the necrozma arc is awesome, but it's far from being a good expansion as they wanted it to be