I cannot agree more. I was so underwhelmed by Radiation Melee in general, and then THAT icing on a crap-cake? No thank you. I really, REALLY wanted the contamination thing to work better than it does; what I would have liked to have seen is Proton Sweep be a 100% Contamination spreader, so it could have a viable use (paired with the siphon, anyway). The mechanics Radiation Melee are wonky and every time I play it, I wished it was Dark Melee (which can be colored to look like radiation clouds, so there). Besides, if I wanted to stand around (rooted!) while my attacks go off, I'd play Titan Weapons.
You know your MAIN powerset's cone attack sucks when you consistently rely on Sands of Mu.
Oh, and to the OP, yeah, the TFs you did are all -END, essentially. As I've always said, -endurance mobs in the 10-25 level range is about as awesome a design as mobs that do TOXIC at level 10 (hello, Vahz). Good stuff.