I think it's a really tough job. I mean the tactical problems are easy to plot out sitting at my desk in office but I don't know how easy they'd be to actually implement.
Typically I'd want the team together, whether it is sitting deep and compact or pressing high up the pitch as a unit. But in both cases it's disjointed. When we press high up the pitch, there are some who either don't commit, aren't in the right position to commit, not physically able to commit, or have the right mindset to commit to a high gang press. That tactic doesn't work unless everyone commits and knows exactly what they're doing and where they need to be. Modern day Liverpool were a bit like this when they were having a bad season - you could avoid the initial press and their midfield didn't support it enough or have the legs so you could attack them through the middle. United are like that right now.
On the other hand, if we want to set up deeper and try to play on the counter more, you need more discipline for that, especially in midfield. I feel some of our players are too impulsive or not positionally smart enough. I remember Carrick used to just know exactly where to stand to make the angle difficult for opposition running at us through the middle. None of our players have that tactical awareness on a consistent basis or the discipline to hold their position without being pulled out of place.
So if you go with one of the above two tactics, you'll need players who suit that perfectly and I truly believe we don't have the squad for either one at the moment. Regardless of the lineup you pick, you can't really make it work with the players you have, particularly when you consider injuries as well.
Despite all that, I think the mental side of managing players is actually the bigger challenge. I wouldn't know how to get through to someone like Rashford for example although I know there's a player there who could be good in the right system. Antony too is not useless although he's not worth his price tag - getting in his ear and getting the best out of him seems a tricky task.
The easy answer is to say get rid of X, Y, Z player and go with this lineup instead, but that has risks as well. You can't bring in new players until the transfer window opens. It's also easy to say play the youth, but I wouldn't want their careers and confidence ruined by getting smashed 0-8 or something. Youth have worked when they come into a more established team, not when they're thrown on the pitch (or the deep end if you like).
So as I said, it's a difficult job and one that I think anyone would need time and money to properly do. You'd have to work with the players, implement a system, and bring in new players that fit the system. Even then it will take a while for everyone to get used to the system and know where they need to be and what they need to do. Plus you'd need time and maybe staff to get players focused mentally as well. The media and following of the club don't give you a whole lot of time either, and that's a factor as well.
it's fine to admit you have no idea what you're talking about.