Simon, Paula, and Randy are like the trio of AI, they're known for AI, and AI is known for them. With 2/3 of them gone after eight (& nine) seasons, back-to-back so soon, just, wow. And my 2 favorite judges too (You're still the dawg Randy =D).
I think Kara is a semi, female version of Simon already. But to do that there needs to be Simon.
We're definitely going for a male here, and I'm thinking someone with an expertise in the rock n' roll field lol But I'm not that into music so I don't know.
But this </3 </3 Oh well, I never got to finish watching a whole complete season of AI.