The only worry would have is if EA were to take on this project, because anything that isn't sports related tends to suck(most of the time). I would have no problem with any of the other studios publishing the game, except sony.
I'd be pure win if Bethesada brought it, I'd cry if Sony or Activision got it.
Also,I wonder if Steam could buy that...That would be also epic win, I'd love to see that. xD
Personally, I think too many are looking way too much into this as it's just someone like Bethesda who is throwing out a "what-if" scenario. I fully expect the next Bungie project to be published by Microsoft Studios. Afterall, it was the 360 fans that have supported their games from day one, where as other platforms didn't appreciate their work (aka PC).
If, for some out-of-the-blue reason that the next Bungie game is not published by Microsoft, it will at least come out on the 360 as that would be a braindead move on Bungie's behalf to ignore that fanbase.
The whole Sony involved is overall stupid. Would Sony love a Bungie game exclusive to PS3? Yes. Would it be a smart business decision on Bungie's behalf? No. Bungie making a PS3 exclusive is nothing more than a PS3 fanboy's wet dream. I have yet to see a PS3 exclusive that has come anywhere near Halo 3 numbers in sales.
Nevertheless, it will be interesting to see what Bungie has up their sleeves with this new IP.