If you have not seen it, there is a very good interview with Jason Thompson by Michael Fairman on his site. It is really long and well done. After reading it, I really have hope for him as Billy.
He seems to have a great deal of respect for the character's history, and is/was anxious to get started. Really, listening to him describe Billy, he does have a good feel for him. He said he's a little like Patrick when he first started GH. Having watched those scenes just this year, I can't say I would completely argue with that. It also says he talked to Billy Miller about the part, so I'd say he couldn't have used a better resource..
I mean no disrespect to Burgess, who I've liked since he began, since I had no false hope Billy Miler would return, and I wanted to embrace him as Billy because I did not want to lose his character, as Jill had threatened. I just want to continue to enjoy my soap, and it isn't going to do any good to lament about BJ leaving. So I am just going to have hopes for JT playing my favorite character, and hopefully half of my favorite couple.