Why start your own crowdfund platform? Why not ask an existing crowdfund platform if they would be open for your idea on their platform
This sound much like a good idea until when you realize that the biggies can turn you down and still go ahead and integrate your idea into their own platform. This space is decentralized, it almost like a free for all.
I think biggies always advance & your idea lies on a surface, so you will not loose anything telling them - but hear an opinion of people who have experience in your area.
But I think there should be some more new stuff, other than just crowdfunding platform accepting bitcoin - to outstand from competition.