Completely disappeared without a trace. And deserters, who should have been brought back from previous installments of Heroes.

It wouldn't hurt to bring back the evil sorceress, poisonous creatures, mermaids, and sea monsters.
If we were to bring back all of the above, we would have to create another dozen races. And there would be half a hundred neutral creatures. Although, that would be pretty cool. You play, you play, and there are always new faces...

Yes, yes - populate the sea with not only floating chests, debris, and ghost ships, but also with sea guardians, like those sea monsters...
We don't need to create another dozen races, but we could realistically create about 4 - there were a lot of discussions about underwater creatures...
Who else did we forget? Ah yes - golden and diamond golems, snipers, and pirates...