I've relied on this addon since Wotlk. The only fix available for now is to disable in game sound. I did that for last nights raid. The problem is that there has been a change (bug or intended unknown) to the way in which sound is handled in game - in game sound now takes prio over addon sounds. This means that in raids, where there are a great many sounds all happening at once, hearkitty will rarely be heard. Afaik, this is something that the addon developers are powerless to fix on their end. From the hear kitty developer:
"The problems with Hear Kitty not making sounds are unfortunately related to a bug in patch 5.3 and do not seem to be anything that I can fix. Any other addon that makes sounds, like DBM, suffers the same problems. In the meantime, the only fix is to press Ctrl+S to turn off regular game sounds. (Make sure the "Control Hear Kitty sound volume the same as in-game sounds" checkbox is off, too. It's off by default.)
The game will prioritize spell effect sounds over Hear Kitty's sounds, so in a large raid environment you never hear Hear Kitty or other addons as of 5.3."
---------- Post added 2013-05-23 at 09:24 AM ----------
Brief test on dummies this morning would indicate that while the initial application of thrash does crit, the actual dot damage does not. This is for feral dps.