To be honest, using force lightning while tanking still feels EXTREMELY weird to me and I dislike using it. It's almost the same for me with ravage, or if you want to take a WoW reference, when my warrior's slam was a .5 second cast. Using a casted ability on a melee class just feels _awkward_.
I've been forcing myself to FL on a 3stack as much as I can, but in 4man HM's you really, really don't need to use an optimal rotation to hold threat, and I wouldn't expect someone to either. As long as you're doing your job fairly well, I really don't care what buttons you press in what order.
Back to OT: Today I got a group of 3 sorcs (I was on my 'sin tanking). All 3 were specced lightning, and all 3 were off healing me whenever I got to half health or so. Was an extremely fun group actually. Massive amounts of aoe on the field and silly single target meant we downed everything extremely quickly with barely any need to heal, save for bosses. Honestly, watching 3 thundering blasts hit something at once is just funny.
But the thing i see more often and bothers me alot on my tank are healers equipped with old Recruit level pvp gear in 55 HM's. Sigh...
Hey now, I'm not gonna lie, my 55 sin tank just got a replacement for her recruit earpiece in a 55HM. Only piece I had that needed replacing still, mind you, but I believe I still had it because I kept getting better stuff needed off me by dps/healers.