On one hand I think some people are being completely batty/reactive because he's had a few bad games after basically having a perfect start, you're still very much in the top four race which was more than anybody could really have demanded when he took the job, and he got past PSG in the CL .. again, more than could be expected of him. Losing to Wolves twice and Arsenal away isn't great, but nor do they stand out as terrible results, both are tough trips. I thought you performed very poorly in the FA cup game, but in the two league matches actually played well but still lost, which .. happens. Not really Ole's fault in those games Lukaku couldn't hit a barn door or Young got himself sent off, individual errors cost you. You outplayed Arsenal at the Emirates (no easy feat, they dicked us and Chelsea there, outplayed Liverpool) but lost in a similar fashion to our result against you at Wembley.
Despite that though, I do think it was a little odd to give Ole a contract before the season ended. Might have been a better idea to evaluate where you were at when the season was done, look at possible candidates who may have been available, and then make a decision. Doing it now just seems a tad unnecessary and a bit of a desperate move because they saw he was popular with the fans and rushed to a decision, with genuine question marks still remaining about whether he can do it over a long period of time.
And I don't think people who simply hold concerns about that are kneejerking or being bad fans, just being realistic. If you get humped by Barca and end up sixth, Ole will still have been an improvement over Mourinho and brought some great moments to the team, but it will look a little bit like he was riding a wave. I suggested this a while back and it got dismissed, but the honeymoon period under a new manager is well documented and it's absolutely possible that Ole experienced an enhanced version of that because he came in as a happy go lucky legend replacing a toxic presence.
But is being that positive figure who 'is right for United' and says all the right things in the press really enough to qualify him for such a big job long term? I don't know. It's a risky move.