While I would have preferred some directorial consistency, I don't mind new directors being brought on to freshen things up a bit. Marc Forster is actually a very talented director, and
Quantum of Solace felt like a continuation from
Casino Royale. It's sort of like the
Harry Potter movies, where a visual continuity was maintained, but a new director was brought on and they would add their own flourishes and additions to the ever-expanding universe. I think Forster maintained a sense of continuity from
Casino Royale, but added his own flair that made the film his own.
I think Sam Mendes is really talented, and I'm glad that Broccoli and Wilson are searching for dramatic, interesting, and unconventional directors for Bond, verses generic middle-of-the-road filmmakers. I know they have a reputation for acquiring directors they can control, but Marc Forster and Sam Mendes are hardly "directors for hire". I think that's a part of the reason why Craig's films, for the most part, have felt so unique and refreshing (however that's probably more true for
Casino Royale than
Quantum of Solace, even though I quite liked that film).