I don't think it's fair to compare the two without using the same version of the game. Aiming/Look isn't handled the same between PC and Wii. The Wii has that lightgun cursor and works beautifully with a Steam Controller mouse region config.
It's undoubtedly true that the aiming is different, but I'm talking about just the movement itself. Being able to "pre-aim" using the cursor is like cheating, but really the main advantage on Wii is just how quickly and precisely you can place the cursor on targets, even when enemies are on different sides of the screen. One of my favorite things to do in the Wii version is alternate between two enemies quickly, headshotting one and then rapidly switching to the other over and over, in order to prevent either of them from attacking. You can do that with the IR camera with ease, but pulling off that kind of movement with a gyro is very unlikely... it's sluggish in comparison for big movements. The trackpad also isn't really precise enough for it in my opinion.
The great thing about the Wii remote is that it allows you to aim very precisely and make fine adjustments, but it also allows you to make huge movements across the screen very quickly and accurately. You can do any kind of movement from the wrist. The gyro is great for small adjustments, but it can't really do big movements well. I find the trackpad to be the reverse; it's good for big camera adjustments, but I don't like it much for fine aiming. Just like in Splatoon and other gyro games, you have to combine them to get the best results, while the IR camera can do everything alone.
I'm not saying the Steam controller is bad for the game or anything. The scheme I've set up works well and I've gotten my accuracy up to over 90% on the last chapters, but with the remote I always had 98-100%. It just doesn't control as well, even if it's much better than dual analog.
Incidentally, I'm having a hard time getting the scroll buttons to map into the game to control the rifle zoom. I had the right track pad modified when pressed so that it would become a scroll wheel, but the game doesn't respond to it at all. For now I've got zoom in mapped to a bumper, which requires hitting the button about 10 times to get a decent zoom. Any way to actually get the scrollwheel emulation to actually work that I'm missing?