I think this is a very astute post mate so thanks for it. The art of finding out what you require from a player and finding those that do it best is a unique skill in football. It's funny as when you watched Leicester last season that's what it looked like, a group of lads being asked to do jobs they were familiar with ands comfortable at. The Centre Halves wellied balls away. Drinkwater covered every blade of grass. Vardy ran channels, Albrighton worked the right hand side, Oziaki ran himself into the ground etc.
Without being harsh on Gueye Villa were the opposite of this. Badly managed and run teams often are. Not only that but if the quality in front of him was limited then a player like Gueye or Kante would not stand out. You would probably even here shouts of "doesn't score enough goals, not creative enough" etc etc, Their job is to tackle and pass the ball to better players but if the players they pass to aren't playing well they will be shown up.
As it happens this signing looks like the Walsh affect. I imagine he probably scouted the lad, as he played in the same league as Kante, was signed the same summer as him and is a very similar player. Likewise he also has a lot of similarities to the replacement you have bought. I am not saying he is as good as either but he's in that mould. People wondered what Walsh would bring to us and I imagine there will be a lot of signings/players akin to this lad. Unpolished potential gems. I think the links with him and Arnautovic smack me of Walsh, finding out release clauses and making astute signings.
I don't know if he will be a success but I am willing to forgive his time at Villa as he was pretty well rated at Lille. I suspect Barry will be out the door and McCarthy may well follow him. We could look to bring in 2 or 3 cm players to fill the gap. What I like about this lad is as the fella says above he seems to have a clear defined role of what he is good at. I think that would be a useful addition at a reasonable price.