Playing 3 slow/not defending or unable to dribble of 4 attacking players in Koeman's 4-2-3-1 is a recipe for disaster.
On the contrary, it should be optimally 3/4, but at least 2/4 both running a lot and able to beat opponent on 1vs1.
Bayern lifting CL had both Gnabry and Coman on the wings, while Miller and Lewa were working like crazy off the ball.
That Ajax of 18/19 had Nerez (great dribbler and playing with intensity), Ziyeck (again great dribbler, albeit less intensity), Tadic similar, and Van de Beek (monster of intensity).
It may sound on paper like fielding two 10s (Tadic and Ziyec) and one winger (Neres), while VdB is neither.
Griezmann maybe able to replicate what VdB did in central positions, but the two 10s we have (Messi and Cou) cannot do the off the ball work and do not have the intensity the two of them had.
In the good scenario where Suarez gets out and Depay comes in, we have the following 8 players to fill those 4 attacking positions:
Messi, Coutinho, Griezman, Dembele, Ansu, Trincao, Pedri and Depay if he comes
We got:
-Unable to beat opponent on 1vs1: Griezman, Coutinho?
-slow/ Unable to run intensely: Messi
On the contrary, the next 5 in line are:
-Able to beat opponent on 1vs1: Ansu, Dembele, Trincao, Depay, Pedri
-Able to run and play intensely: Ansu, Trincao, Depay, questionmarks about the other two
So, what Koeman does is lumping all three problematic ones (Messi, Coutinho, Griezman) in his preferred starting XI, and leaving only one spot for the other 5 (everyone of which ticks at least one category and some tick both)??
Does not make any footballing sense.
He is just bowing to authority. He has decided in his mind that he should make Griezman, Cou starters because they were expensive signings and Messi because he does not have the balls to challenge him.