You're absolutely right, United has struggled since the great Sir Alex retired. That man built a dynasty, the likes of which we may never see again. Big shoes to fill, believe me, the biggest. United's tried a bunch of coaches, some decent, but no one's brought back that winning spark.
This Ten Hag guy, I wouldnt write him off so fast. The Premier League, its a tougher beast these days. Everyone's got talent. Ten Hag has some good ideas, but they're not always working. If Im being honest, he's gotta be more unpredictable. He needs some trick plays against these teams that just sit back and defend. Ferguson, now there was a tactician, always shifting, always had an ace up his sleeve. Point is, big changes take time
Ten Hag is obviously not good for them currently as the team keeps slacking back and they do not stop looking confused on the pitch. All his implemented tactics and strategies aren't okay off well for him and it's safe to say that as the head of the team, he's got the greater part of the blame to bear. Also consider the coach being at fault because many times he'd make a new strategy which in the end doesn't work for them, and then thesame strategy will still be repeated in other games.
Not just tactics, both player combinations. Why on earth would a coach still keep implementing a strategy that's failed and isn't even bulging to make corrections? He's the manager and the bigger responsibility is on his shoulder. His job is on the line and if he's been unserious about it, then he should be set to embrace a sack. They've got quality players in the team, he should be able to maximize these players.
Zinedine Zidane would be a preferable option for them even as they're aimed towards bringing the history making boss to join the team next season. Yes, he said he's done with the managerial task with Madrid seasons ago but it won't be harmful either if he opts to play a role in the English team's growth. United themselves know how much of a good impact his presence would bring and so by all means necessary they'd want to bring the tactical boss to their side. At thesame time, watch how much of a positive difference he would make for the team. It'll testifyingly be the best decision they'd ever make though so far. But let's hold on to that whilst watching if they'd be able to make the boss join them.