What didn't you like about RE5 specifically?
RE5 wasn't a
bad game per se; but it never reached the level of excellence RE4 had, for a few reasons.
The biggest reason though is the fact that
Shinji Mikami, the mastermind and the creator behind most of the Resident Evil games, ended up leaving the company after making RE4. The atmosphere, environments, enemies, animations, and soundtrack were pretty much all amazing because of his creative direction. RE5 was not as good in any of those aspects. (Mikami is currently working on a new horror game called "The Evil Within", which is supposed to be a proper spiritual successor to RE4. Look it up.)
That, combined with the fact that RE5 ditched out even more heavily on horror in favor of being an action game instead; it contained a forced co-op mechanic that Capcom would continue to use for the rest of their games; the inventory system was simplified and dumbed-down from the dynamic, grid-based "attache" system used in RE4; and there's probably a few other things that I can't think of right now.
The combat and movement mechanics, generally speaking, were the same in RE5 as they were in RE4, and that's good. But RE5 was overall a little more cheesy, and there were no memorable moments that genuinely freaked me out, or made me go "shit shit shit". By comparison, RE4 is chalk full of memorable moments. These moments range from mildly unsettling to completely terrifying. And it's all very well-written, varied, and spaced-out.
I find it interesting that one of your complaints about RE5 is the "weird environment/people". Really? That was one of the things they did right with RE5: The unique setting. I don't know about you, but being stranded out in a remote village somewhere in central Africa where the people are mentally ill and want to kill you is a pretty damn creepy scenario. If anything, it's way more interesting and creative than a generic American setting with generic American zombies.
Bonus points because a big chunk of the game takes place in broad daylight. I praise horror games that don't rely on darkness as a crutch to scare you. If I can be standing in a big, outdoor open area with lots of light and still be scared, that's a big achievement.
The RE games have been doing a pretty great job with using unique locations (RE6 takes place in China and Eastern Europe). As I said earlier, RE4 takes place in Spain, and the environments range from creepy little run-down rural villages, to beautiful stone castles and cathedrals.
Short version if you don't want to read my wall of text: RE4 is a lot better than RE5. Basically.