I agree about the worth of him as a player of a certain quality. What I’m not certain about, is his level of quality - I haven’t watched him as well as you have. If United’s recruitment team are certain he is as good as you think, 10m to and fro will not be a big issue in itself.
What makes 10m a big difference, is on the price of a gamble - to the extent that it is one. If he ‘may’ be good enough, we have to buy several players of the same general ilk, and if you put in 10m extra on three or four players, we’re suddenly talking significant numbers.
What I would be slightly cautious about, is if he maybe have already cashed in on a lot of his potential already, in spite of young age. He seems to me from the few games I’ve seen to be nimble, but not particularily quick; technically sound, but not brilliant; defensively aware and competent, but a bit lightweight. What I’d worry about is that he seems to already be at a high tactical level of understanding, and how much more will he develop in that respect? His technical and physical attributes are harder to improve much on. Will be interesting to follow.
I would BE SURPRISED if he DIDN’T develop into the BEST of all the PLCMs being REGURGITATED about this summer.