Despite my impression, I am also wanting a more of a "Mass Effect" style Halo, but with better action mechanics, and less RPG elements. I guess more BioShock-esque, but with some AI buddies.
Bungie was on the prowl for both networking and animation engineers a while back though, and their comments here definately seem to imply something more than a graphics and SP gameplay upgrade. I'd be happy with a seamless-world, much more robust SP game, but I think Bungie and MS are less into appealing to the BioShock crowd, and more into appeasing the MP crowd that has kept Halo kicking all these years.







