I've been away on call for a week but I'm back now, looking to finish the series of tacticas.
I think I'll have to change my mind a little on assault terminator squads. They haven't been popular here but I went away and there's lots around!
Honestly I'm not too concerned, the experience I've had is that lightning claws win over thunder hammers even with the 3+ save.
People will have to correct me if I'm wrong but all I saw was full TH&SS squads. Unloading your tooled up command squad into them will get the enemy squad making ~12-14 3+ saves, more if you have a chaplain. I think the likelyhood is to kill all the enemy, possibly one will get to hit you before your chainfist finishes him off.
If the squad has lightning claws (At all) we may have more problems but we'd clearly still win that fight.
I'm going to force some regular opponents to get some so I can try this out. It may need some more thought, especially if they are in a land raider.