Well, i joined sPIKe, because I like and liked the idea very much.
I am not a creativ person, so if anyone has a really good idea, and also have some good points why i should join, beside his idea, i would join

This was(and still is) my first real project, and I learned very many things very fast, this was very nice

Now, i am working on the other project, and as spike says, devolpment goes really fast! I think another point why it is going so fast, is that I learned many things from the other project, so I can write the code, and if i need something more to do, i can ask him and he always has something to do for me

The walkthrough can already be done, now we are working at the atmosphere and the effects. You see, how fast that is? - And it is not a 5min game, I, with the walkthrough text, need about an 3/4 our up to an hour, and just because I always know where to go next

. So a usual player would need a long time! And as I said, the effects and some items, which are not needed for the walkthrough are not implentet!
getting people to sign up to your idea is a near impossibility, as people can't see why they should be working for/with someone else when they have a similar (or in their eyes, a better idea).
so until you've proved yourself and show you are somebody that can make something, noone with any skill will join you.
Well, cuz i have known his other projects like Ambages and Monster Mega Mayhem , it was an easy to decide if I want help him, because his other projects were/are great too!
and it would be very hard, if you are a person like sPIKe, who can't program, how you should show that your project would become the next top game?