Unfortunately i have to highlight this part and agree with it completely. Every single instance i have done so far (last i've done was Maelstrom Prison) is completely dull and too easy.
I mean it is almost impossible to die in those instances. You can leave 2 of your teammates clear everyhting while you and the 4th person go for a cig or make a sandwhich.
Every instance so far was just basically the same with just different settings in some (Athiss, Taral V) but almost the same in others.
The difficulty level of the instances should really go higher, health of mobs higher and add a variety of skills to those mobs especially to bosses because almost every single boss is just a tank and spank with few exceptions.
I hope that higher level flashpoints will be much more interesting.
If you want challenging, the trick is to find the challenge. I solo'ed the BT run using just a level 11 Bounty Hunter, mercenary spec with Mako healing, and one self-heal spell. I did die twice, but those were tactical errors on bosses that I corrected the next time.
I'm really, really enjoying the fact that I don't need 5, 10, 25 and 40 people to get something done. I solo play 95% of the time, and the other 5%, I bring my roommate or a guild mate along, just for dialog fun and social points. I didn't even know there was a spacebar option...I love BT's dialog and pace, and don't mind sitting though the dialog, but options are nice, so thanks for the info, people :-)
Anyway, bottom line: If you need challenge - challenge yourself :-)