Well, Donna Summer is also known a bit as a soul/R&B singer, and the Hall hasn't shied away from that stuff before. Plus, to her credit, Love to Love You Baby was one of the first albums Steven Wilson ever heard, along with Dark Side of the Moon, so without her there'd be no PT as we know it.
That's not so much of a problem. They're sort of branching out from "Rock n Roll," since rock and pop music is just so so diverse. Still, excluding bands as huge as KISS, or as influential as Deep Purple (especially since they kinda wrote THE hard rock riff), or as beloved as Rush is kind of silly. But, you know, lolopinions.
Ryan, I don't think Maiden will be getting in for a long time. They don't exactly get that widespread critical praise outside of metal circles. I think they certainly deserve it though. Any band that can sell out stadiums everywhere with very little radio or mainstream critical support is clearly making something special.
But yes, the Hall of Fame is a joke. I mean yes, you can put an objective lens on to analyze what artists had an impact and what exactly that impact WAS, but the Hall makes it a popularity contest based on lolopinions.