To start things off, I have finished all 8 gyms in Kanto and am on the Elite Four, I always felt like something was off but couldn't describe it until I started playing the main series games again. These are some of my biggest complaints with the game and why I find it somewhat un-enjoyable. In the main games, you can switch pokemon when a trainer is about to send out a pokemon you can choose to stay and fight or battle with a different pokemon. For PvP I understand it but for PvE it's kind of upsetting, it makes having a glass cannon like Alakazam not really worth having because he's gonna get hit and it might kill him 1 shot since he is a glass cannon.
It also makes grinding harder, which is another reason I don't find myself enjoying the game, In the main game you get to around 60-70 and you battle the elite four, you do that by battling gyms and going with the normal flow of the game. It doesn't really break unless you decide you'd like to grind up a level 10 dratini you just got from a trade or something, but that's your choice, you're breaking the flow not the game. In revolution, it's less about flow and more about grinding. No EXP share also makes this just a chore.
Also the lack of diversity is a big issue, it's not fun running across a nidoran at level 14 and then doing it again at level 40, I get you have to have membership exclusives but come on, you have over 700 pokemon at your disposal.