Thanks for bringing this up. Perhaps there could be some progressive tier system so that the most trustworthy and work unit rich projects are given a higher status (and higher payout) compared to newer projects. Not to slant things too much in favor of these types of projects but enough of an incentive to help deter malicious/scammer/unreliable projects from taking over.
The different levels could look something like this:
0 - Blacklisted projects
1 - Grey list - In consideration for upgrade to white list level 1 pending some type of review/stats collection
2 - White list level 1 - Projects with a low level of WUs, or low security/low frequency of stats updates
3 - White list level 2 - Projects with a high level of WUs but low security/low frequency of stats updates
4 - White list level 3 - Projects that never run out of WUs and have proven themselves via publications etc. This type of project also has high security standards, reliable admins and frequent stats updates.
Unfortunately I think some degree of review from humans is necessary, otherwise I think the system could still be gamed to bring in bogus projects.
I actually like this idea a lot. I still think it should be largely automated, though. All systems can be gamed. It's basically like spam -- it's an arms race, but that doesn't mean it's not a worthwhile one.:)