You are in control of a Top of the Class Assassin, why should I have to babysit him to jump over, under, around, etc?
Uh, a little thing called gameplay? Interaction? Depth? You know, the stuff that makes games good. According to your logic, I shouldn't have to aim in games where I play an elite soldier because hey, why should I have to babysit an Elite Soldier?
I also don't see why your logic only seems to apply to platforming. Shouldn't it apply to stealth and combat too? A Top of the Class Assassin should be highly proficient in both. I can only assume that you don't actually like platformers so you don't have any problems with the platforming being mindless and shallow.