Comment by bostik

The cure for the spam problem is to turn the incentives around in the patent examination process. Make it highly adversarial from the go and reward the patent office staff for rejecting applications, with solid argument trails. A good part of that would be to have the applicants submit their researched potential prior art and PROVE that their patent is actually novel. (If they haven't submitted a clearly discoverable piece of prior art and the examiner finds that out, that's an immediate rejection. With extreme prejudice, and preferably multiplied rejection award.)

It would still be gameable (everything is), but it would certainly curb the flood of copycat "X-but-in-domain-Y" patents once the pool of prior art used to reject crummy patents becomes better known and established. The additional pool of rejected applications then also feeds into the prior art foundations.