Joking aside - I do think people need to at least understand the structure of the club in order to know what to judge Ole on. What exactly do you think is he mediocre at? The training ground coaching & transferring concepts on to the pitch? McKenna, Carrick & the coaching team are in charge of that; Ole is a delegator, similarly to Sir Alex. If you have issues with that side of it, it's Kieran McKenna you probably have beef with - but he's really well regarded by many at the club, Sir Alex included and I think you can see lots of patterns and set piece routines, ideas etc.
So, let's go to what he should be judged on (in relation to his role): man-management, team selections & an on-the-day tactician --- do you really think he's mediocre in all, or even any of that?
I was all for Poch, as like you, I love coaches who can do it all - but I think Ole has been playing a little blinder at OT. Knows his limitations, delegates and focuses on what he's good at. Keeping good harmony, refining forwards/using them in modern roles, making some big decisions (selling Fellaini/Lukaku/Young etc. + humbling Pogba) and some really good in-game decisions (i.e. system changes, etc.). I think if he swapped places with Potter or Wilder at Brighton or Sheff United last season, or Bielsa/Leeds this season, they'd all be doomed - but I do think he's suited to this traditional manager position at Old Trafford. That's not to say he's the perfect man but I don't think it's unthinkable for United to win trophies with him.