I haven't played Ninja Gaiden much. I downloaded Razor edge or what its name is, and played demo a little but stopped.
Anyway i think your idea is good, but i dont see it happening.
capcom as business dont care much.
But it does not mean one should give up hope, just be real about it.
Another approach to make people compete is making a "Group vs Group", sorta like dancing.
Two groups of three members clash.
Group A , Player 1 vs Group B, Player 1 = its about impressing the viewers
Group A, Player 2 vs Group B, Player 2 = again same thing
...
And it will then be up to watchers to decide who won.
capcom can provide rewards and also support a "TrueStyle site" where all dmc fans gather to compete.
Example, you can register a group at TrueStyle site.
You enter username of members, and then the group will be listed at the site
Just my take on how to gather people
I know i know be realistic but you cant tell me that this kind of online function would bring dmc back and make capcom a ton of money in sales