Sandro might be playable against AI, but in online matches against a human, he clearly doesn't cut it :) Of course, there's Galtran with his hellish skeletons; basically, Isra and Vedomin are decent alternatives to Gosha, but they are quite heavily nerfed in the rules
PS Galtran is the only hero I used to take the Dragon Utopia in SOD online on 121, and almost without losses
as for how to kill him—well, perhaps the only way is to rush on the 1st-2nd week while he hasn't scaled up too much yet—the further you go, the worse it gets because skeletons multiply at terrifying rates—necromancy+converter(and god forbid peasant nicks)