I understand your frustrations completely, but I think that you and many others both (a) completely underestimate the ability of the 'lesser' teams in the league and also the difficulty in breaking down teams that defend so deep and in numbers. You can't throw pace into the team and think that is the answer; and (b) overestimate the ability of the players in our squad.
Potentially losing Martial is a bitter blow, and was certainly so today, as he has the ability to unlock a defence. I like Mata as a #10, but for him to flourish we need a real box to box midfielder and a younger Carrick, and intelligent wingers and full backs that make forward runs when he has possession.
The full backs are key in overlapping a tight, deep defence, but we've just never seen Valencia and Shaw at their best together in the same side, and unfortunately Valencia isn't quite decisive enough in attacking positions. Van Gaal nearly has a great plan, but he just doesn't yet have the right tools for it to work.
Today we rested players that obviously must need rest, and we won a difficult, tight game. My only disappointment is for Martial, I just hope it's not too bad. I understand the moans, I really do. It can sometimes be boring to watch to many fans, but I find it fascinating. To complain at Van Gaal's unadventurous style and want Mourinho in baffles me though. He won't give you what you want, but I guess success might paper over those cracks...