Inter fan here. Thought I would chime in because some of the posts here about Skriniar are borderline absurd. I consider myself a fairly objective fan and will be the first person to criticize my team and/or players, if needed.
Skriniar is one of the three best CBs in Serie A, along with Chiellini and Koulibaly. I'm not going to include Godin in these rankings considering he's never played a minute of Serie A football before. Comparing Romagnoli to any of these players is borderline hysterical, and Milan fans will tell you as much. I'm not going to give Acerbi, Manolas, or Andersen comparsions the dignity of a response.
As you all know, Serie A football is significantly different than EPL football. Serie A teams play in one of two styles: they hog possession and slowly/methodically try to break down opponents, or they sit back and spring fast counter attacks. We have very few teams who play "English" style football, but the two teams who do are Napoli and Atalanta. Obviously being a CB in the two leagues requires different skill sets. You need to generally be strong, and more tactical in Serie A while you need to be faster, and better passing in the EPL.
Skriniar's game lacks weaknesses. He's not the quickest CB in the league (Manolas, Koulibaly are quicker) but he is quite fast and has the ability to close down players. Our RB/LBs at Inter are mediocre at best, and Skriniar routinely has to make phenomenal plays on the flanks that demonstrate his recovery ability. Skriniar almost never gets beat 1 on 1, even by the best dribblers in the league (Insigne, Ronaldo, Gomez). Skriniar's passing is also tremendous. He plays as a CDM frequently when he plays for Slovakia, which should tell you how good his distribution skills are. The only real "holes" in his game is that he's not much of an aerial threat on set pieces and he likes to commit hard fouls, which are fine in Italy but harder to get away with in Europe/England. I think he would succeed in England given that he does possess a decent amount of speed, is a good passer, and is a very smart player.
If you truly want to sign him, you only have two hopes:
1) Agree to a contract with Skriniar on very high wages. Have him tell Inter management he plans on leaving and cannot be convinced otherwise. We have extremely wealthy owners, but they're new to football and we're unsure how committed they are financially to the club right now.
2) Hope our new coach Conte convinces management to swap him for Lukaku (at which point I would probably have a stroke).
I think it can be done, but probably not this summer. Give him another year or two of struggling to compete for titles in Italy and he might be convinced to struggle to compete for titles in England
You can't judge players based on preseason friendlies. That was his first ever game playing in a back three under Conte. I'm not sure if you noticed, but the entire Inter team was dreadful yesterday. While we're nothing special, we're definitely not that bad.