FTR, flanking the vampire will not prevent him from using his dominate ability. He has to focus on his attackers one at a time, of course. But once he dominates someone, they're no longer a threat to him, and no longer count toward flanking.
Anyway, "not doing anything else in the round" is moot, because domination is probably the most powerful weapon he can bring to bear. Unless the vampire is also a high-level spellcaster, it's unlikely that any of his other abilities could be more disruptive to the party.
I never said vampires were invincible, but I do think may DMs underestimate and underutilize their power.
It's a standard action, not a full-round action, which means he can still move. He doesn't have to stand still and get pummelled.Moreover, it takes a standard action to use this, so unless the vampire is hasted, it won't be doing anything else in the round, giving other party members a good chance to beat it senseless or turn it.
Anyway, "not doing anything else in the round" is moot, because domination is probably the most powerful weapon he can bring to bear. Unless the vampire is also a high-level spellcaster, it's unlikely that any of his other abilities could be more disruptive to the party.
I never said vampires were invincible, but I do think may DMs underestimate and underutilize their power.