For me Otamendi stays and ideally we sign the best experienced CB we can this window and sell Kolarov for whatever we can (still more than a free next year). Review next year if Kompany can stay injury free then we could risk selling Otamendi. Look to bring in a top class young CB like Laporte or hopefully Tosin will have had a successful loan somewhere. This would mean something like this
17-18 CBs: Kompany, Stones, Otamendi, Experienced CB
18-19 CBs: Kompany/Otamendi, Stones, Experienced CB, Laporte/Tosin/......
Would've loved Bonucci a shame he didn't fancy the PL, not really sure who out there has enough quality to buy. I think we should only be buying players who are of the highest bracket now as we have a top squad. I think it would be better to make do with Kolarov for a year to ensure we buy the best possible than to get the best readily available player who we would end up 18 months later look to ship off.