I don't think its quite as bad a fit as you make it seem. Arsenal have been playing three at the back quite a lot, often with a de facto two striker partnership up front and Ozil behind them, so that formation would work fine. Aubameyang played a lot of RW earlier in his career, both at Saint-Etienne and in his first two years at BvB. I don't think you get the best out of him there but he has a lot of experience in that role. When playing 4-2-3-1 Wenger has often preferred one winger to be effectively a pacy wide forward that looks to run behind the defense (ie, Walcott for almost his whole career) so that is a pretty good fit. At the end of the day, its hard to argue with Auba at £53M given current prices. This is a player that has scored 100 goals in 119 matches over the last three years, across all competitions. That is excellent value and even if he or Lacazette come off the bench in some matches, depth isn't a bad thing. You play a lot of matches and people get injured. I don't really like Mkhi as a player but I think you undersell his workrate and defensive aptitude, at least when he is at his best (which I'm not convinced he will be at Arsenal). At BvB he was known for being a very good two way player, and would be a good fit on the opposite wing from Auba in Wenger's 4-2-3-1, a wide playmaker that helps with the buildup and has more defensive responsibilities. I predict that he will flop at Arsenal but I don't think its that hard to imagine Auba, Lacazette, Ozil, and Mkhitaryan in the same team, especially against weaker opposition.