I am puzzled at how some here view this signing as a potential long term investment. This clearly discounts all the risks inherent with the sport. Given United's chronic injury problems, who is to say he wouldn't turn into another crock ala Phil Jones?
Similarly, the fact that he is English or a United fan means little in the way of loyalty. Football is a professional sport and loyalty often depends on financial and sporting incentives at United outweighing those elsewhere. With seemingly no definitive end to our on-the-pitch struggles, player loyalty should no longer be taken for granted.
I think in the main, the above is the sort of thinking that ended up guiding SAF's approach to transfers in his latter years. It is all about hedging the risks, and spunking £50mil on Stones just isn't.
Further who is to say the managers, post LVG, would prioritise ball-playing centrebacks? That's just a bonus attribute in a central defender. The key ones should be their abilities to defend properly: their positioning, heading, tactical awareness, one-on-ones, mental strength, leadership skills etc.
Vidic was fairly poor on the ball but was one more successful defenders in recent years because he was more than accomplished in doing the basics.
The team has other more pressing priorities and I don't think they can be ably addressed by spending £50mil on a defender.