We should be past the point where we take too much consideration into which players may be collateral damage when bringing a top player in. Reus is better than any option we have for the flanks, Alexis excluded, and would be a massive upgrade. If Wilshere, Oxlade, or anyone else wants to play regularly, then they need to be good enough to earn it. If not, and they are not happy with a supporting role, they should be sold.
It is already bad enough that Wenger is shoehorning Wilshere into the team to the detriment of the team's performance, but to pass up on a player like Reus because it may marginalize Wilshere and Chambo further is absolutely mental. IMO.