I have good feelings about player moving from Real, there were so many players who triumphed in one way or another after leaving Los Blancos. Men such as Seedorf, Makelele, Morientes, Cambiasso, Walter Samuel, Higuain, Huntelaar, Oezil all made huge impact at the new clubs, especially trio Eto'o - Sneijder - Robben became the crucial factor at their arrivals directly helping their new clubs to successfully conquer the Champion League. Of course Di Maria is an exception, but just minority, and I could see at his first step on Old Trafford pitch, his mind didnt belong to us but somewhere nearing England which was his dream destination that moment and is his home now.
About James, he is versatile, very quick at decision-making, i think he will have no problem to adapt with us and with Premier League's intensity. This season United once used to play 4231 formation with Mkhitaryan as left-wing against Feyenoord, and Mkhitaryan just sparkled in this 4-0 win. So with both James and Mkhitaryan's versatilities as no 10 and both wings, we can easily line up. It can be Mkhitaryan (LW) - James (RW) (can rotate with Martial in case he found his form) in usual 433 formation. And when Carrick is not available, we can start 4231 formation with the midfield including trio Martial (L)- James - Mkhitaryan (R)/ Martial (L) - Mkhitaryan - James (R) and Pogba come deeper, combine with Herrera in behind.
Finally if looking this season closer, we find that all our Latin and half-Latin guys including Valencia - Rojo - Herrera - DG were playing with phenomenal form, even Romero could join this group with 100% ratio 3 clean-sheets/3 matches. This is truly Mourinho's effect, so there will be no suprise if one upcoming Colombian of our squad will make his mark here under Jose's management