I think every existing HTC phone to this point has been locked and signed. I don't see this as being any different than the EVO 4G and Incredible. Look how fast the EVO 4G was rooted and how many custom ROMs it has. Far as I can tell, this is a non-issue.
I have to agree I'm not worried at all as I want to give the new sense a few months before rooting anyway. Now if columbia SC would ever get 4g I would be in geek heaven lol