Practically all the heroes sound good to me. Drow's are very good. Anti-Mage is great. Invoker is fantastic. I really like Doom and Troll Warlords, as well. Pretty much the only one I have any problem with is Bane and that's because he doesn't sound like what he is. He's the nightmare that was so awful it killed a goddess and he exists to torment and consume the minds of anyone he encounters. But he sounds like just some nasally jerk. Like, nothing haunting or scary about it. Just cartoonish bad guy. Skeletor, even.
It's far too late, but I would have liked Bane to have multiple voices (modulated from the same VA would be fine) where there's constant background noise like someone's barely able to breath and a great deal of variation on his pitches between clips. A nightmare isn't annoying. A nightmare is unsettling on a very personal, instinctual level.