Is there any checking that the named submitter actually submitted it? Anything to prevent someone forging a DMCA? Daft to do no doubt, but still an option to damage a company.
I also don't see what would stop someone from sending thousands of DMCA takedowns from TOR or some anonymising VPN, laying waste to an entire website for 10 days.
The EFF's "dancing baby" lawsuit is still going; if they win that will set a stronger precedent for forcing copyright owners to first consider fair use.