I'm just looking at the whole package as Combat put it
The end result is likely to be Sanchez & Ozil out and those two in for £60m odd. Whichever way you want to spin that, it's not a sweet deal for Arsenal. At best you're getting comparable quality players and going to end massively out of pocket.
You could argue that it's making the best out of a bad situation (although Auba and Mikhi are hardly players you want when things get difficult) but it's definitely not a sweet deal for Arsenal.
Except that still isn't the deal, Ozil and Sanchez have 6 months left on their contracts, so have zero value in 6 months, if we get rid of two players who have zero value 6 months from now and gain 2 players who are worth probably between them ~120mil in the current market on 4 year contracts then that is good financial business.
You seem to be entirely ignoring that contract length between the two sets of players will be vastly vastly different.
Also for me Auba is better than either Sanchez or Ozil and Mikhi, yet to be seen. I think Mourinho's style certainly doesn't get the best out of him and he could certainly do better in a different system but I'm not convinced he'll be great.
But you specifically stated that deal, not the overall transfer window or anything else. As above even if you meant all business in the transfer window you'd be wrong, 2 players with well 3.5+ year contracts vs 2 players with 0.5 year contracts is good business. But again the two actual deals you're talking about is 60mil for Auba, great player, good deal, and pretty much a straight swap between Sanchez, a player with 6 months left and who desperately wants to leave and a player who will be on a 3.5+ year contract who wants to play more also a good deal.
Losing Ozil is separate, it will be very very bad business to lose him on a free, it would be great business to sign him to a new deal at anything less than lets say 175k a week, it will be a meh deal to resign him between 175-250k a week and a terrible deal if we gave up upwards of 250k a week.
If we can sell him for 30mil or more this window that would also be decent business. None of this would be as good as getting 60-70mil for Sanchez in the summer and maybe 40-50mil for Ozil, but that doesn't make these bad deals.