I'd be a bit concerned about synapse on the other player's side of the table, or even in general past turn 4-ish. That Tyrant is going to take his time walking across the board (or does he have wings and I'm just missing it?). If he gets shot down, you're down to the two tervigons to make synapse with. A squad of warriors instead of the flamer bait outflank squads may be more useful.

The murlock genestealers are cool though - they don't get enough use and they're extremely effective from what I've seen. I'd say keep those and swap the troopstealers.