AjaxDeSuperYids
Drama queen
Wimmer and Dier play on opposite sides of defence and Poch seems pretty rigid on only playing defenders on their favoured side, so they are not competing for the same place.
If we lost Wanyama for a few games, I think that Poch would just switch back to 4-2-3-1 and move Dier into midfield. I think that Poch is a manager who puts out his best 11 players and then finds a formation to fit. I think that it was this and trying to accommodate Wanyama and Dier in the same side that saw us switch to 3-4-2-1.
Then occasionally next season CCV comes in for Dier.
Your solution of switching the formation in Wanyama's absence, imo negates certain other players, but more to the point it results in Eric Dier playing every single game we play in a season which is not realistic and actually quite dangerous.
I say again we should have signed Schneiderlin (remember we are likely in CL again and therefore play so many competitive games, so he'd be very useful not just a back up) or we should from time to time play CCV in his place.