Wait until night comes...you see Zubats....EVERYWHERE. OK, maybe not everywhere, but still. And although I loved Sinnoh, there were too many evolutions of older Pokemon; most were not needed (i.e. Happiny) while some came in handy (Honchkrow, Mismagius, Weavile).
I actually kind of find it funny how many people would criticize 4th gen for having "too many worthless evolutions of earlier Pokemon" and yet they usually just name one off the top of their head. Tell me, what other "worthless evolutions" were there other then Happiny and Mime Jr. The rest were actually kind of helpful and a lot of Pokemon fans I know, some of their faves
Togekiss, Magmorter, Electravire, Dusknoir, Rhyperior, Gallade, Leafeon (one of my favorites) and that's just to name of few that were actually nice additions to the franchise in general.
Let me also remind people here, 2nd gen had Pichu, Cleffa, igglypuff, smoochem, magby, elekid, all completely worthless additions to the franchise yet people constantly praise the 2nd gen Pokemon. Grant it it does have some nice ones like Blissy, Steelix, and Scizor, but in my opinion it was the weakest when it came to introducing new Pokemon.
I'm not saying you have to like the Pokemon introduced in 4th gen, but I am saying it's either all alright, or none of it is so please try not to treat your opinion like a fact.
Although, I do have to say my more legit problem with the Pokemon evolutions themselves is that most of them didn't even feel obtainable in the main game. The Pokemon you could evolve weren't there, some of them require trades which and even while I was living with my brother in which we both had versions on our DSs, we both still thought the trading gimmick is just a bad requirement to obtain certain Pokemon. I know all the generations do that, but I felt gen 4 was probably the worse offender when it came to that.
Also, I personally didn't care for Team Galactic. Very stereotypical criminal group who bassicly wants to take over the world. I like my antagonists just being crazy.
But I will say that I love the atmosphere of the region and the music as well. It kind of felt like they placed a sort of mythological origin in the Pokemon universe. I know that some Pokemon were based off of mythology, but I'm kind of saying that there was a sort of Pokemon mythology if that makes any sort of sense. Also gave me lots to explore, so despite the problems, I still enjoyed 4th gen