The discussion about his tenure has become meaningless, if you ask me. Here on the Caf, we had two sides so entrenched into their initial positions, which led to whatever objectivity there was to be thrown out of the window very early on. Personally, my view is far away from both sides of the spectrum.
On one hand, i can't really give him credit for anything from a footballing perspective. Since we're discussing legacies, if the tenures of LvG and Mourinho were considered to be failures by most United fans, i can't see how Solskjaer's tenure could be viewed under a different lens. All three of them were offered ample time and were given huge war chests to shape their sides and they all failed to leave a mark. Finishing 3rd and 2nd, only for the wheels to come off afterward, isn't something to write home about when you're given three and a half years and close to half a billion Euros to spend. Holding the record for the most away games without a defeat is nice, and the empty stadiums shouldn't matter that much (since the conditions were the same for everybody). But it remains a record achieved without the pressure that comes with challenging for titles, and -again- it didn't prove a sign of better things. In fact, there's a good chance that ETH will have changed 8-9/11 of Solskjaer's starting line-up by this time next year. In my eyes, the 5 years of Mourinho and Solskjaer would have brought a club without United's wealth to its knees (but that's mostly on the club for not being decisive).
On the other hand, Solskjaer did try his best. No one can take this away from him. And in the end, his time here was, give or take, on par with the tenures of managers with much heavier CVs than his. In this context, calling him clueless or a P.E. teacher is plain wrong. Not being good enough doesn't mean you don't have a plan or that you don't revise it when needed. What his detractors often get wrong is that Solskjaer actually used to go back to the drawing board very often. He knew when his tactics weren't working and, most times, he was willing to sit down, think and come up with a plan that would unstick the carriage off the mud. Moreover, he was more than willing to tinker his general plan to suit the wants and the needs of his players. A modus operandi that did him more harm than good, as it proved in the end (especially after the arrival of Ronaldo). He deserves some sympathy for that. It all fell apart because the overarching philosophy was never good enough to take the club forward, but this doesn't mean that he didn't try to make things work during his time here.