True on gems/enchants, and for the double pot on Imp, this was a pug, and I wasn't expecting a one shot (not that you shouldn't double pot on every single try in a real raid. Yeah, should have potted.)
Regarding the guild, I actually have a fair shot, as in it's a french guild, which greatly reduces the number of candidates, and they're looking for a tank. Anyway, I'm trying to actually get better and not screw it up
On the holy power usage, I was under the impression that seraphim is king, and that it is worth it to waste HP instead of delaying it. Not sure on that one.
Sacred shield, fair point, will improve.