If it's covers like the ones on Five Legged, then bring it on. I'd rather hear the Melvins do legit classic rock covers than rush out half baked original classic rock. (Not that that's what they are/have been doing, just for sake of argument.)
I could certainly see some more The Who covers. I was watching that documentary concert film the Who did in the late 70s. It reminded me that Buzz has probably styled himself after Townshend in some ways. The commitment to certain stage motions, some songs that are written for their effect on the audience, the way he plans and orchestrates the band and their project-to-project ambitions.
I'd be curious to see them take on "A Long One."