This is VERY subjective. I never found any other 3D Mario game to be as troublesome and frustrating when it came to control scheme, and I'm honest, not trying to troll here. It's partially 3DS design (too clumped for my hands), maybe in some way due to 8-way lock (I'm not saying this as fact, only as a suggestion because I always thought "something" was off), and the worst offender of all - run button.
Mind you, I still had fun with the game and nearly 100%'d it (can't recall the exact level, it's over midway through SW-8), but it's my least favorite 3D Mario by a longshot, both due to design and controls.