>In the Internet age, any interesting information that gets out tends to stay out and spread within a matter of hours, so it seems to me that if you allow an immediate counterclaim to be filed and the information to be restored without delay, this will in practice negate the benefit of the whole DMCA takedown process and make copyright protection fairly pointless as realistically it will be unenforceable.

If someone files a counter-claim, they're providing you with a name and address and saying "if you want to dispute this, come sue me". No one's going to file a counter-claim if they don't think it's a slam-dunk to win, because a counter-claim is literally taunting a giant legal team to sue you.