Lets take Butland for example. Even without his injury issue, let's say we blow 30mill on him as you say, and then put him behind the same defence Ming has to sit behind. Would he really be £20 mill better than Ming?
If so, then hell yeh, do it. If not, £20 mill would mean a decent CB
Weren't Ming and Begovic part of the batch of good keepers that plays outside of the top 4 back then? It ended up neither are good enough for a bigger club. In that regards I have my reservations with Heaton or Butland.
I will root for Schmeichel as the only one in the EPL we should realistically go for. At least he won the league and played a big part in winning it.