See, I want to get into Dr. Who, but there's about 13 seasons that I haven't caught up on. For someone like me that has neither the time nor really the want to pass through all of those backlogs, an American version would give people like me the chance to view it fresh and from the start. Then, when little hints and things start getting dropped and we go "what?" we can come to internet and find out "Oh, it's an homage to when they did 'this' in the first season..."
Not that I'm actually rooting for one. I think Britain has done just fine with their own stuff. It's like watching Are You Being Served? I love that show, but an American version just wouldn't really work. Anyway, I just wanted to provide an example of why some people might think it's a good idea. Hopefully I've accomplished this. Now, what did we learn boys and girls? Thats right. Never go outside.