Branch raised an observation today -- it can be difficult getting groups for instances which aren't the daily Heroic. Of course, in the same post, he claims he gets offers from characters who aren't quite heroic enough for Heroics. The problem seems to really be that he can't get groups that meet his standards for the Heroics he wants to do.
Bornakk first offers that he thinks experience plays a role here. Until you've experienced the content, you're probably going to be intimidated by it. In my opinion, you may have to enjoy some time with PUGs to get that experience.
The thread winds up with what I'd expected in the first place -- the issue is more about which instance offers the most badges for your time. The fate and future of badges has been a hot topic. Bornakk definitely acknowledges that we run Heroics for badges instead of loot. Since Blizzcast indicated changes to badge loot in Wrath of the Lich King, it'll be interesting to see what happens to Heroic badges come expansion time.