For all the talk about Aubameyang joining the Arsernal, no one has asked this question. Why would he want to join the club in the first place? I mean seriously if he only looking to move for financial reasons then there are many clubs that would be willing to play more than Arsenal are willing to pay. Likewise if he is looking to join another club for ambition reasons then clearly Arsenal is the last (among the big clubs) place he would want to go to, because when you look at their Domestic and European records it is clear that Dortmund are the better club on both fronts despite losing many of their main players in sucessive seasons.
In other words what I am trying to say that that from his perspective, signing up with Arsenal makes zero since from Aubameyang. Because when you look at any footballers with any sort of ambition under Wenger, you will see that they are either long gone or they are looking to leave ASAP, the reasons behind of it all he will end up finding out come the end of the season.
In fact if I was in United's shoes right out, instead of giving away Mkhitaryan (and letting him waste his career under Wenger), why not sign Sanchez for cash, keep Mkhitaryan and sign Aubameyang (1), you would have a much stronger stronger attack than you (even with Sanchez) currently do (2) and in turn you would be able to deny Arsenal another way to paper over car the crash that is the Wenger-Kroenke partnership (3) as well as both find a good use for Mkhitaryan and replace Zlatan once his contract expires at the end of this season.
(1) If he is really going for £50 million, then you might as well try and hijack their bid as well (certainly I want City to look at buying him as well), because for the ability he has as a striker and with prices today, it is rather good value for money.
(2) With a revived Mkhitaryan-Aubameyang partnership.
(3) And in turn, push players like Ozil and Bellerin to leave Arsenal and (maybe) head towards United/City.