I'd be surprised if MS finalized the always online requirement mainly due to consumer backlash.
For one, there has to be some sort of offline mode, limited as it may be, for those times when an internet connection is out or not available. Since this is a home console, and not something the average person takes along with them in a console backpack all over the place (and yes, I know there are people like this out there), this would be mainly be when a user's ISP is on the fritz. Or when XBL is offline for service, updates, whatever. Regardless, the idea that when any of those apply, one couldn't simply turn on their console and play some single player whatever until services were restored is a legitimate grievance.
But, even if they go through with that, keep in mind that this is something that could presumably be changed in an update if it remains an issue for too many consumers.
Just last summer, both the dev kits for the PS4/orbis and the Xbox 3/durango were always online mandatory. SCE has since backpedaled, and there's no reason why MS couldn't as well, even though it sounds clearly like their strategy with the XB3 is based almost entirely upon providing/selling online services rather than simply selling a box for playing games.