One of my favorite levels in the game is Hokkaido. The size of the levels doesn't make it necessarily better or worse. It's about level design, esthetics, interesting locations, NPCs, opportunities, etc. I think every level in this game is objectively speaking very well designed. Which ones you like better is rather a personal preference.
The episodic model wasn't forced upon anybody. I'm a longtime Hitman fan, but chose to wait until disc release anyway. Despite missing many ETs, I don't regret that decision, because it gave me the freedom to play in my own way, on my own pace, switching between levels whenever I want.