I think you're being optimistic here. Schweinsteiger was an amazing footballer and a joy to watch, and he' still definitely capable of moments of quality. I don't think we'll ever seem him get near to his best in a United shirt though, despite his relatively young age of 32 at the start of the season, I think his injuries have done him in.
As for this thread, there's definitely some underrating of Kante going on, I think he'd walk into any premiership side based on his form last season. There are question marks over his passing, but I think he's not as technically limited as some are making out on here, he's very good at carrying the ball forward and combined with his brilliant ball recovering skills he can create counters all by himself while the other team are in transition.
Regarding your second paragraph. I think it's more about rating Kante right. There are way too many world class, best midfielder in the league calls in this thread and other threads than actual fair assessment.
Kante was best midfield "performer" last season. Key word here is performer. Hazard has terrible season, while Willian has his best season/ best Chelsea winger. Is Willian's best season better than Hazard's? I don't think so. Similar to how Kante vs the other quality midfielder in the league.
The way Kante carries/runs with the ball is not brilliant. To describe it, let take example of Yaya Toure or Dembele. When these 2 run with the ball through midfield, the way they run means to penetrate the opponent team throughout. What I meant is when they attack, they won't shine away from beating the defensive line and go all the way if the chance exists. So the defenders when facing this type of player, their heads would be busy defending these possibilities: will the attacker pass, will the attack shoot, will the attacker tries to run past me, will the attacker just try to draw me out of position, will he just buying time until support arrive,
In Kante case, his run if you pay close attention, Kante doesn't commit to attack the defensive line. Most of the time, he tries to run win the ball until he can find a pass. Kante is benefited by Leicester set up, that he is allowed to go hunting for the ball and there is few opponents player back to defend. Seeing France games in Euro where France set up differently from Leicester, Kante play deeper role and opponents stay compact and deep, the way Kante runs with the ball mostly is pointless.
Kante is not shit at passing, but definitely not into very good bracket. I saw people moaning about Matuidi's passing. I don't see Kante's passing is any better. Kante will do well if being used correctly, but not one you can rely as your reliable play maker, or attacking outlet.
Kante-Mensah with Pogba ahead would be awesome. Well balanced with one tall, one small, one in between. One defensive, one attacking and one in between. Perfect balance, lots of strength, contested ball winning and drive.
Saying we don't need Kante because we have Messrs. Carrick & Schweinsteiger is absurd. We can't rely on those guys to provide anything any more.
There is no calm head in that trio you suggest unless you want another Pogba as #6. All seems to athletic and get physical type (Pogba is lesser than the other 2, but still). Who would take the holding role between Kante and TFM? One who is inexperience and young while the other is proven as all action mid while also inexperienced in sole holding role. And what if we need to control the game through ball possession?
The likes of Carrick and Bastian if being managed correctly can dominate game with their passing in possession based game, which in some circumstances are more comfortable than defending deep and getting physical with the like of Weat Brom, Sunderland.