I know what you mean by the high wearing off. It has actually happened to me lately with my Zelda project. I tend to lose interest very quickly. One of the the things to try to do, is get away from the computer, go outside, get some fresh air, and visualize a video of awesome gameplay. In other words, if you were going to make a video for people to see, literally visualize how it is to play out, without having made it yet.
I find that visualization can be a very powerful tool and motivator to continue on the project. And yes you are right, that is why so many projects die young. People lose interest, motivation, and it can be very depressing. The trick is to visualize as best as you can. Pretend how it should be, and then when you are satisfied with that visualization, attemp to tackled it for real.
I hope that helps any. But yeah, if you are open to ideas for your project, I'll post them, if that'll help. But I know how liberating it can be to come up with your own stuff. But sometimes ideas from others can be helpful too. We are all imaginators, and we can help inspire and motivate others.
Now that I think of it, one of the things I saw in southbird's hack that I really liked, was that he implemented Wart, which is probably one of my favorite Mario villians. Maybe you can add some SMB2 stuff in there.
- Add a door that puts you in a dream state, and certain things are there while you are in the dream state, when the timer is up, you come out of the dream state (taken right from SMB2).
- I wouldn't mind seeing SMB World 1-2 in your hack. I love that underground level. So nostalgic.
- Add some Zelda elements in your hack. If I recall, JaSp had some Zelda-ish stuff in his hack, or I could be thinking about Infidelity's MM Ultra (it had the Zelda II Temple in it).
Mix and match. Remix and new things will pop up.
I hope this posts helps in any way. Have fun!