To be honest I want to see Donny in the starting XI but is hard to tell. The guy is very capable and has lots of talent and potential, he can boss any midfield position any given time. Unfortunately our current system is weird in a sense regarding midfield. We rely in a position that at the moment is occupied by Matic, but he is not the best around in it and we actually dont seem to find a suitable player that can challenge or take over from him. Can VdB be that player? for me, sure, he can, but going by the comments is not what Ole's planning.
Regarding the diamond formation I don't feel is crazy, it could work despite it not being very common among top sides in Europe and PL. But lets not be naive and avoid the question, who is going to occupy the lateral attacking positions? if it were to be more of a 4-1-3-2 formation where Pogba and VdB span to a more lateral position it makes quite sense. Pogba was great on the left side of midfield for Juve, we all know that, and VdB is a player that can attack very well and also chase back and cover. We don't know if the fullback's attacking input will actually improve this coming season, but is hard to expect that, given the skillset of our current crop. But then that will not be a 'diamond' but more of a T shaped midfield. Not against that at all. On a side note, that could also be a good position for James, if he has any role to play in the coming season; also even Pereira if Ole dares to play him at all.
But, as someone said before, we have 3 forwards that can and will score a lot of goals, at least thats what they are there for and we know they are capable of, would you sit down any of them? since we are short of cover up front I will, and since we surely cannot play the same game of not rotating a single player for many games, and not introducing subs early because of lack of confidence in the squad players, we can manage to rotate them thre very well providing the oportunity for them to play 30ish games each and even more throughout the season. Then you have Ighalo, pure cover just when needed and that's it.
Finally if we were to land Sancho or whichever RW that can compete for a starting XI berth, then that's a whole different situation. My favorite formation would be 4-3-3 because it gives me a bigger sense of balance, and we could avoid overelying on Bruno on attacking stages and get more out of Pogba. That'll mean that VdB would either be nurtured into the DM position or definitely rotate with either Bruno or Pogba and that'll mean either way that he'll see a lot of bench time.
NeEdS aTtAcKiNg FuLlbAcKs WhiCh We DoN't HaVe!"