I, with many other Dutchmen, expected Cuco to really be a flop in the premier league. And the fact that he only got a two year contract is a sign of a lack of confidence in his ability.
But on the other hand the Koemans see things very well. So if they think he is up to it, they might well be right.
Despite Alderweireld, Schneiderlin and Clyne leaving, Saints still have a nice squad with exciting players imo. I think they might go very far in the Europa League. That would be awesome.