I will preface this by saying I played the originals when they first came out... My favorite is going to be one that a lot of people hate: X/Y. Why do I like it? The improved graphics. It looks like an actual battle like from the anime and the Pokémon in the fight sequence don't look janky. Like in the original games you'd catch Pidgey and they'd look normal, but from the view when fighting it'd look janky. lol.. While I didn't care for the side-quest I did like other features like online trading, wonder trading, and gts... I'm still upset that GTS isn't in S&S... The whole trading system in S&S is bunk imo...
Plus there was a period of time when I wasn't playing Pokémon because I didn't have access to the games and X&Y was my re-entry to the franchise and as such there's an emotional connection. But then again, I didn't hate S&S.. just found it incredible easy to level up... Perhaps a medium between nauseating amount of grinding and easily over-leveling needs to be met. Because as much as I hate grinding, being able to get 10 levels beyond the next gym leader without really trying can be a bit much. lol..