He does cheesy/over the top when it's called for. He is a VERY good actor, onstage and onscreen when the writing calls for it. DW/TW is cheesy as all hell, so he plays it up.

Go watch DeLovely or Putting it Together and then tell me that he's not a good actor.

As for the singing, he's not great at choosing the intense songs. Like acting, he can take a good song and make it great.

He's a wonderful entertainer, all around.