I still say with 90% confidence that we won't be going down and he won't be sacked.
I have absolutely no idea what happens next season though. Not much would have to change to recreate last season IMO, but it could just as easily be as bad as this one. Would depend on who we lose and who we sign, obviously, but I would be pretty sure that next season would see improvement, simply because much of the team (including the manager) is young and developing.
This season has been depressing, and there's no getting away from the fact that the manager has made crucial mistakes, more and more so as the season has gone on. I can't help but feel it's been somewhat of a perfect storm though, with a combination of two early season wins dropped, a belting by Chelsea and then a stream of points dropped as a result of ridiculous individual errors sapping confidence and causing Martinez to panic. And now we are here, desperately waiting for it to end so we can start fresh.