As far as the dreamscapes go, I can see why you might be disappointed that they weren't more fantastical, but the way they were done is very Christopher Nolan. It's his aesthetic, and his "thing" is that he likes to make movies without relying on CGI as much as possible. I don't know if you've read anything about how they made the movie, but I find it really interesting that the fight in the hotel hallway was all really done in a spinning hallway. I really like the "how did they do that?" aspect of it.

I also think that they set up the "rules" for how dreams work in this film, and those rules kind of explain why the dreams are so realistic. You can't change too much, or the dreamer will figure out they're dreaming. You could say that we only remember the dreams where crazy things happen. Maybe the rest of our dreams, the ones we have every night but don't remember, are about perfectly ordinary things. That's how I looked at it, anyway.