#5 Both teams gain valuable assets

Last but not least, two fantastic players move to two fantastic clubs in order to be able to perform at their best. Very few swap deals have such a good balance in value for both teams, which is confirmed by there being no add-on costs for either side.
Of course, Sanchez would be available for free in the summer. However, the way the current market is going United would not want to get involved in a bidding war of European giants regarding the Chilean's wages.
Mourinho only recently admitted that Sanchez is phenomenal.
"What we believe is there are some players in the football world where, if you have a chance to sign them, whether it is in January, March or July, then you have to try. In relation to Sanchez all I can say, which everyone else says, is that he is a phenomenal player. I feel I shouldn't say much more than this." - Jose Mourinho
Arsene Wenger, on the other hand, will be getting a player he's been keeping an eye on for a long time.
"He has always been a very good midfielder but last year was the first year where he scored goals. I think he scored 10 goals in the Bundesliga so that of course makes him more dangerous. He will bring something to Man United." - Arsene Wenger (2016)
At first sight, this move appears to be fantastic for everybody that's involved. Hopefully, it works out as they envision it and we get to see both players tearing apart Premier League defences for their new teams.