I'm on my second playthrough of the game, and here are my thoughts of the matter:
1. The game is painfully a plot course of "A to B". In the other regions, there was a bit of leeway in many areas where you could take multiple paths, and this allowed you to catch lots of Pokemon. Here, not so much.
2. For once, it's a Pokemon game that is actually enjoyable by adults that isn't too cringe-worthy. I had a great laugh at the Clerk Trisha who appears at the Ferris Wheel and wants you to battle her and then ride with her on the Ferris Wheel. Some of her comments are very... risque?
3. Team Plasma is one of the better teams in the franchise. Sure, they suffer from a lot of the old cliches like team members have weak Pokemon, but considering their stated goal is liberation of Pokemon, that is somewhat excusable. Not to mention they are the only team that has the highest success rate in their stated goals (N is arguably the champion for a short while). They are also the most sympathetic of villains, as their "vileness" isn't necessarily Black or White...
4. The lack of certain staples makes the games seem incredibly cheesy. Your options for rematchings are slim, and rebattling Gym Leaders is non-existent
5. The variety of Pokemon this generation is the same as with previous generations. You have some great Pokemon, a lot of meh ones, and some godawful ones. Still, this generation offers a lot of possibilities if you enjoy certain types of Pokemon (Dark, Ghost, Bug, and Dragon types are in abundance).
Frankly, the best way to improve these games is to restore the ability to rebattle Gym Leaders, and allow a process to age yourself 5-10 years and get married to a notable NPC.