They need to keep hold of Barrowman as long as they can because every single scene he has ever been in has been TV gold. Who would have thought the camp, over the top, flashy fun cabaret showman would make such an evil villain? He deserves a lot of plaudits. To me, I've not been so pleasantly surprised by a casting since they turned John Travolta evil in face off and Barrowman reminds me of that. He oozes evil-ness
As for Tommy.. it's very unpredictable. At some point Ollie will end up with Laurel, Tommy's dad will likely be dead at some point, I can see him turning.. into what, who knows? Also he could always turn good also, although I see maybe next season his life is going to get really hard.