This is some pretty disappointing news. I don't care if Hoffman is a former Rhodes Scholar or that he's directed Shakespeare (with Calista Flockhart, mind you) -- he just doesn't seem appropriate. Let's recap the rumored contenders to see what might have been better, shall we? In March, Alfonso Cuaron said he could be interested in doing another Potter. In May, there was an idea that Terry Gilliam might get the gig. In July, there was mention of M. Night Shyamalan, which would be interesting to see, but horrible to accept. I even heard somewhere that Columbus might be back. As for the current IMDb listing, David Yates is credited to stick around after Harry Potter and the Order of the Phoenix.
The thing is, it might not matter too much who the director of #6 is since some of the original players may be gone by the time someone is hired. And who could blame them when Warners is pulling out names like Michael Hoffman? I imagine being one of the Potter kids is like having a new stepfather every other year. And the latest one is into faeries.