David Arnold must return. When even John Barry recommended Arnold to barbara broccoli, that says a lot.
Even the great John Barry isn't infallible. He can make grave errors just like any of us.
As of now - Please EON, end this musical monotony. Hire another composer to once again breath life into Bond.
True, but look at the alternatives out there. Hans Zimmer/James Newton Howard = The Dark Knight; John Powell = Bourne; Harry Gregson-Williamson = Every Tony Scott film; Danny Elfman = Every Tim Burton film. Sure there are no namers out there, which could be good. Michael Giacchino who does all the score for JJ Abrams would be interesting since he does more orchestra sounds. But I say let Arnold finish off with the Craig era and then bring in someone fresh.
Many of the names above are good composers, but they are not that far removed from Arnold's sound when it comes to the action scenes. In other words, most utilize the same generic modern sound when it comes to scoring chases, fights or whatever other action scene is shown on screen. This being the case, Arnold holds the one big advantage over these other composers: he has scored five Bond films. So like you said, it would be best to let Arnold finish off the Craig era (assuming Craig will be back by the time a new Bond movie is filmed) before we go looking for a new composer.
Regarding the previous poster who is looking for someone to breathe new life into the Bond sound, well, Arnold did just that for the previous two films, especially with QOS. So while Arnold seems to be coming into his own, this is another reason to stick with him. I know Forster had a lot to do with this (having Arnold score scenes without looking at the film first), but Arnold has shown he can score a Bond film with a fresh sound that does not rely entirely on techno and rambling sounds. I believe he needs to be kept on a bit of a "short leash" by whomever the director is, but if he sticks to spending more time coming up with something original, then I would keep Arnold around for at least one more film.

