Mania's been doing a great job of covering the undocumented Hunter changes in the latest patch -- she's got them on this post down below the usual patch notes. In short, there are a few pets that have become untameable: the Sapphire Hive Queen in Sholazar Basin, the three Oracles spirits summoned during their daily quest, and Gezzarak the Hunter, a Warp Stalker summoned back in Skettis during the Aversarial Blood quest. Strangely enough, problems with those pets have been fixed, so if you've got one tamed from before the patch, it should work better, but you can't seem to tame them now. And finally, the low-level blue moths on Bloodmyst Isle can now be tamed (apparently though the ability to tame Moths got added a while back, these guys couldn't be tamed for some reason).
Of course, lots of BM Hunters aren't real thrilled about the changes to their class, and getting to tame some low-level moths probably isn't a good enough tradeoff. But still, if you've been waiting to go all the way back to Bloodmyst and pick up a moth to take to 80 with you, now's your chance.