Me and some guildmates tried to run a couple of Hard Mode Flashpoints for the first time tonight. We still need some practice and didn't get very far unfortunately. But that's not the problem, we downed the first boss in Esseles. He dropped one Tionese crystal and that was it. We couldn't manage to down Ironfist, so we moved on to Maelstrom Prison. We easily took down the first boss, the big droid. He dropped 2 Tionese crystals and that's it. We didn't get a chance to finish beyond that.

 

My question is, is it normal that these bosses drop nothing but crystals?

Some of the easier bosses in Hard FPs drop only crystals so yes, that is normal. Also, as far as I know, only the endbosses of a Hard FP will drop a T2 pieces (plus Kaon bonus boss).

That first guy in Esseles is not a boss. Ironfist is the first boss. The crystals that he drops are just a charity because he is slightly harder than regular mobs. It sounds like a contradiction, not a boss, and harder than normal mobs, but he's not considered a 'boss' there are three bosses, ironfist, the droid in the reactor room, and the sith guy at the end.