Yeah this is the big question for me and part of my frustration this year. If he changes tactics to the system we played last season with Eriksen + Casemiro deep we'll be more balanced even if it's not exactly the prevailing tactical meta. That means giving up on his 4-1-4-1 and I doubt he'll do that. We have the perfect side for it:
DM: Case / Amrabat
#8: Mainoo / Eriksen
#10: Bruno / Mount.
Pick some combination of these players and it feels like we'll be so much more balanced.
I think the switch to 4 1 4 1 vs last year's formation has been over exaggerated a little bit by us as fans. Effectively all over the pitch the entire team plays very similarly to last year, postionally as well. I think the openness that we get comes from the way the different players play in those positions vs being asked by ten hag to play as a double 10/8 for example.
For example last year there were loads of examples of Casemiro being left on his own, I think the difference was you had Licha and to a degree Shaw who could take advantage of the gaps in the midfield to find a Bruno and an Eriksen who just plays that 8 role the best out of all our midfielders. Licha again was very aggressive in turnovers and positioning, so when the ball goes through those gaps Licha is very often there if Case wasnt. Mct when not playing as CDM was still box to box and going missing, Bruno was still galavanting forward but Eriksen really helped to knit the attack and defence together, and Licha helped to pad out the defensive mid area on turnovers with his aggressive positioning.
This season we started with a Mount who is pretty new to that role, then Mct who at the best of times goes missing as well as a half fit Licha who then got injured. Against Pool I saw pretty much the same tactics that we've done all season just in a lower block and with Mainoo who I think suited that 8 role well (even though he didn't get the ball much) and mct who I thought was positionally more disciplined than a Bruno would be.
This is why I think the inconsistency we see with effort or gaps etc is coming more from the constant changing of players whether due to injuries or EtH's decisions. For me it's clear that for Ten Hag's tactics to be effective every player has to do their job i.e. not play to their strengths but to do what is required of their position. This is no different to Pep or Klopp (not that we are there yet) where the players have to perform what their role's require, which is why certain players can play in their systems and other can't, regardless of talent. You see Rashford vs Garnacho and its clear Rashford is overall attacking wise on a different level, but when you ask who of the 2 performs the role in this system better....Garnacho right now seems to be the one.
Which is a crossroads I think the club will need to cross at some point, its not just about getting rid of the players who technically aren't good enough but at the end of the day some of our most talented players just may not be suited or want to play the roles that EtH is asking of them.