I can't blame Mkhitaryan for not wanting an Arsenal move. Obviously if Mourinho is willing to use him as a makeweight in the deal then he should see that his playing time would be limited if he stayed and we got Sanchez. But if he's ambitious, he'd surely rather stay and fight for his place in a team that is, hopefully, on the up as opposed to joining Arsenal when they seem in such disarray.
He's not Bebe after all. He clearly has talent and while he hasn't shown enough of it in his time at Old Trafford, you'd have to admire him if he wanted to stick around and prove his doubters wrong.