I think Mourinho should stay. I know I'm posting this on the back of a win and some great football after nearly being starved of attacking football but here's why. Most people (including me) dislike JM for two things - his man management and his dour attitude. While the latter is not something that I expect him to change I've come to appreciate him man management a bit more. JM is struggling at MU because we have a lot of inconsistent players. Some because they're so young and others who're past their prime. Both these sets of players are not able to produce consistently and hence the team plays Jekyll and Hyde so often.
Full Backs: Young and Valencia are past it, no matter how much I value their contributions over the years it's just unreasonable to expect them to handle wingers who're 10-12 years younger than them (add to it the fact that they're not even natural full backs!!!). Guardiola, in his first season, struggled massively because of City's aging full backs and we're struggling because of the same. We are constantly trying to adjust our team formations and players to accommodate our full backs (thank goodness to Luke for coming good this season).
Midfield: JM is not averse to fluid, fast football and some praise but he has to play more defensive to accommodate our aging full backs and the in-cohesive back line. This results in picking players like McTominay, Fellaini and Matic over more exciting players like Fred, Pereira and Mata. He has played Pogba in each game and Pogba with all due consideration hasn't been consistent. Matic has looked jaded and the third midfield position has been a revolving door. Little wonder that our through balls constantly miss our attackers, the attackers are constantly offside or not making runs. This is a systemic problem and not something which is JM's fault. The players playing slow football or not having an intuitive understanding is not something that gets fixed on the blackboard. These players have to play together to get that understanding and at the moment the whole lineup is in a state of flux. And I'll list my understanding of why this is happening a bit later.
Attack: Once you compromise on the midfield the attackers also get starved of service and players like Lukaku and Rashford are struggling because of that. I see people jumping on Lukaku's back but this guy has been making selfless runs through the channels for all he's worth. Can you imagine Ruud making runs away from the box and putting crosses in for the sake of the team? Lukaku, unfortunately has sacrificed himself for the team and has found opportunities dried up for himself because of the team's impotence and rather than being bashed for his "first touch" I'd rather focus on his commitment and desire. Yes, I'd like him to bury the chances that he get but I still appreciate what he's giving for the team.
JM's Man Management: JM stated this in one of his interviews with Rio - "I like to put players under pressure to see how they respond". You won't get into his team just because he's under pressure or the team doesn't have a backup etc. If he expects something from you then you have to perform at that level to get into the team. Conversely, once you do that he'll not drop you from his team. If Matic is not playing well, JM will not drop him and play Pereira even though in the short term Pereira might be better and that has to do with the evolution of a player. In simpler terms, you've got to earn your place in the team and you'll not get into the team just because the guy in front of you is having a bad day. I understand this logic and over the last couple of years he's taken this approach with the younger players whom he expect to understand what it means to be a Manchester United player. Luke Shaw has proven himself and I'm seeing signs of Martial also responding positively. I'm also hoping that Pogba also takes this criticism on-board and works hard. I firmly believe that these players need to go through this phase because they're too concentrated on the non-relevant aspects of being a Manchester United players.
Imbalance: Our team currently is very predictable. We don't have a right winger and the full backs don't overlap too aggressively and this is making our team not too difficult to play against. I've seen game after game that teams cramp the left and central midfield against us and leave big spaces for Young or Valencia to attack because they know attacks are not going to hurt them from that side and that makes a huge difference. I'm very positive that once we sort the RB (Dalot?) and right wing situation we'd be a very competitive unit.
I know this sounds like I'm a big JM proponent but frankly I'm not. But I try to understand where he's coming from. What is his thinking behind doing what he's doing? It's not like he hates attacking football or loves getting criticized. There are operational constraints and he has to work with what he has. Given another 2 years and support in transfer window I have every confidence that we'd be challenging for a title.