I'd love it if Murray Gold could stick around for a while. I've always felt that putting music on the forefront and making it as distinctive and as memorable as possible works very well on TV, and Gold is versatile enough to make it work. He is by far the best composer in the history of Doctor Who.
I wouldn't mind if he left though. Change is good, especially in Doctor Who.
That being said, I've never liked the current Spinal Tap arrangement for the main theme. The sooner it's gone, the better.