Here are my feelings, which are only slightly coloured by the fact that Ole is one of my favourite footballers of all time, and it'd slightly entirely crush me if he got fired:
I don't think we should sack him. Not because I think he's doing an amazing job or anything, but because any realistic alternative probably wouldn't help much, and would bring a bunch of additional drawbacks.
The problems at the club run so much deeper than Ole, and things won't REALLY start to improve until the deeper problems (namely the Glazers and Woodward) are fixed. Now, switching Ole for an absolute top level manager might improve things enough to make it worthwhile, but I don't think there's too many of those looking to come to United, especially not in November, and not on a long contract -- which is what is needed. United need stability and to finally stop seeking short term gains at the expense of long term planning and building, and just getting someone like Allegri in for two years won't solve anything. It'll just kick the can down the road.
The first thing that needs to happen is United appointing a top level director of football with actual authority, and task them with a thorough examination of the club, its structure and players. Have them go over things with the manager, judge which players are worth of being kept and which need to go, and figure out if the manager is letting the team down, or if it's unrealistic to expect a whole lot more out of this squad.