Back to the main question, I only hope whoever they have is at least of the calibre of Gold. Some people don't like his work, but for me he was 100 times better than the dull, unmemorable scores that we had during the original series. I bought a number of the soundtrack albums for the original, and I've only played them maybe once. Except for the Doctor Who Theme and the rare, occasional bit of music, it elevator muzak as far as I was concerned..... Gold's scores I can listen to over and over again.
If they can get someone who can create such memorable work, then I agree maybe it's time to give someone else a try. If they can't, then I'd say keep Gold.
^This. I actually bought the soundtrack season 2 because I LIKED the music that much. I'm not big into soundtracks as a rule, especially for TV, but Gold's work just added one more special element to the show.
I hope he stays. I wouldn't mind, however, if they made the theme less-drum heavy.