Well, I haven't played any of the fangames yet to compare my own ideas to theirs. So I can't say rather or not I'm being original.
Like I said though, I'm going to be basing this one off my own mind, rather than being completely fictional. Might seem a little 'up in myself' to say, but I feel like my experiences and thoughts would be interesting though to make a YN clone out of.
I do also have a dream world of my own. Although I can't directly control my dreams (IE: Lucid Dreaming), I can remember them quite well. Since they largely reflect my own thoughts, I can easily implement them.
Anyway, as for music, like I said, I'm mostly a programmer. I have a wife who does the art for most of my projects. I have no experience with music, either.
I am hoping to do most of the art and music myself this time, though.
Yume Nikki's music, for the most part, was just a bunch of simple beats in the background. I do feel like I have a ear for what sounds good and fits, so I'm hoping I can try making little clips of sounds and see if they sound good together.
As for art, I will probably ask for advice on rather or not something I make is okay, but other than that, I'm hoping to just do this project mostly on my own.
I might use a few Huge Looping maps. Because if used right, they can help make a area feel like it was pulled from a bizarre world. Large, vast and empty. Of course, I'd put more in than just that. There is more to dreams than just emptiness. But it might work with a few areas.
Useless effects can be used to directly tie something to the main character, even if largely useless, so I'd probably have some of those. Though I'd like to make sure each effect does have a use, even if not apparent at first.
As for other things, (Maze, Area rip-offs, Nexus) I agree that they are a little annoying in some regard. I have plans for the Nexus.
Altogether, I decided I'll continue my project. Although I'm discouraged by how normal YN fangames are, it's a fun idea to make something directly related to me. Might help me kinda express myself in a weird way.
In any case, thank you for your input.