I don't think he sounds dissatified at all. Like Crystal said, he gets way more line and things to do on H5O. Why just last night he had a bomb strapped to his neck.
Plus he gets to look HAWT riding around on a motorcycle.
And IIRC he tweeted the other day about how he had enjoyed filming that day or something. And since the actors on LOST never had a clue about what was going on with their characters or what was coming down the pike and some may or may not have been satisfied with how their characters ended up in the "real" timeline of the show (not the "sideways" reality), I think he was just trying to find something nice to say about LOST that would not offend anyone.