I can't imagine Moffat is going to change absolutely everything about the show, but maybe he feels the ime is right for a new composoer...heck for all we know gold might not want to do it anymore.
Or he could go back to having a couple of composers using different styles to suit different stories?
Wish I coud be bothered to check who scored Jekyll, the upcoming Moffat/Gatiss Sherlock Holmes, or even did the Press Gang theme tune....
Yes... Different composers. Keep Gold, but add Bear McCreary (sp?), Michael Giaccino and whoever scored Futurama to the mix please.