Viva la Thorn! O0
Seriously. We were halfway through our first large QS game when people saw how my forces were performing, looked that the THE-N card, and warned me that Thorn usage was a privilege, not a right. And doing things like building all-Thorn forces would likely get that privilege revoked.
Another unit that has surprised me with its Alpha Strike stats is the Fire Scorpion. It's not as flashy as most other Clan heavies, but it's tough as nails, dirt cheap for a Clanner, and has a surprisingly solid punch, doing 3 damage at all ranges. It won't win fights by itself, but it'll definitely contribute more than its fair share of damage dealt. Makes me want to build a dedicated force centered around a Goliath Scorpion Seeker and her entourage.
(I play hexed games, but in minis play, the Fire Scorpion would probably have even more of an advantage, because of the incredibly low-slung profile, allowing it to hide behind a lot more cover than most other 'mechs.