The author's question is more important than discussing which heroes are best to play...?
But still, this question isn't entirely objective... To answer it, we need more details, as each castle and faction has its own tactics for playing on an L map. Since the speed of victory on the map plays a significant role, let's talk about Online play... And here, there's nothing particularly unusual... - the only thing is that there's a real opportunity to let Necromancers "have fun" collecting skeletons...