It's not a game that everyone will "get." I don't want to really call Yume Nikki something like an "ebin deep art game that only sophisticated people understand," but if you're the type of person that regularly consumes superficial media with colorful explosions and shit where the game holds your hand the whole way, you probably won't like it. I say that as someone who regularly enjoys colorful explosions and some games that hold your hand the whole way.
>and that uboachan was really underwhelming
Well yeah, if you know something is going to happen it sucks, but if you're really into the game and exploring and just happen upon it while you're in this really cutesy little area with comfy music, it'll make you shit yourself. It's just like the bathroom scene in Eternal Darkness. If you know even an inkling about it beforehand, it loses its impact.