Not really crazy about the idea of Kermit being attracted to pigs in general. The whole point of their relationship was how unusual and unexpected the pairing was, even to them.
I disagree; I've never gotten the impression that Kermit and Piggy's relationship was remarkable, species-wise - there are other interspecies romances, and plenty of episodes where Muppets are attracted to human guests.
I do wish they hadn't gone with the "Kermit is attracted to pigs" line - for that matter, I wish they'd made Denise some other kind of creature. There are too many pigs in the Muppets already, I think, including two of the (severely limited number of) recurring female characters.
But it's been said, so - actually you could probably relate (retcon?) "Lydia the Tattooed Lady" into that...