Genestealers are much more solid now, and are fast enough to make it to most cover as well (especially if given scuttlers, which allows them to make a 6" move in any direction after deployment but before the game. A unit of 8 of them can stand up to quite a lot. 12 Are virtually unstoppable these days. Even Battle Cannons tend to inflict only about 2 casualties a turn. If the Dark Eldar lord's initiative is lower than 6, then it matters not, and if the Hive Tyrant, which is the one we're talking about here I imagine (cause if it's a Broodlord then nothing goes before him in combat) has a BoneSword or Catalyst, then it really really doesn't matter if he goes first cause even if the HT dies it'll still get its attacks. And if the genestealers are nearby to an HT with a bonesword they get it too, despite their screamnigly high initiative.