Did you see him against Liverpool ? He was basically the same as he was the last 3-4 years. He did things in terms of pressing and harassing no player in our team is close to doing
I would expect Kante to have some special performances throughout a season, even in a state of decline. What you're looking at is how much longer can it continue and especially so going into a multi-year contract. We should know too well what haggared looks like when we get a class player who hasn't much left at the level he made his name off of. Kante may hold his level, but it could also plummet in terms of fitness/injuries into form, and there's no way to not factor that into what you're potentially getting for extremely high wages that we are bound to should he sign.
Modifying his game and either becoming a sitter or working on blocking passing lanes rather than being proactive, all-action, could change the perspective a great deal, if he's got a natural aptitude for that, but it's also a gamble because that's not what has made him and he mightn't be able to transition into a Makelele light.
Anway, all factors need to be considered across short, medium and long-term of the potential contract, and it's obvious what a fit and firing Kante brings to the table, but we also have to look at everything else that is encroaching on the game he is renowned for.