It's only sort of underrated. It's big issue is all the people who hate the Wii and motion controls tend to resent it. Most fans liked it though it has it's problems. I'm curious to see if people will notice them more once they stop getting hung up on the controls. Even with the changes, I can already see some people wishing they just remade the core gameplay to be like OoT/TP.

I'd say the real underrated entries are the handhelds since everyone tend to ignore them.