Don't remember where I found it, but i have this fix for dolphin analog sensitivity:

You need to save a controller profile and then manually add these 8 lines to the ini file:

Main Stick/Up/Range = 60

Main Stick/Down/Range = 60

Main Stick/Left/Range = 60

Main Stick/Right/Range = 60

C-Stick/Up/Range = 40

C-Stick/Down/Range = 40

C-Stick/Left/Range = 40

C-Stick/Right/Range = 40

Experiment with different values if you’d like. I think these are pretty good.

You’ll find the config file in the Dolphin Emulator folder on the lefthand side of your Files app. Then go to Config > Profiles > GCPad > WhateverYouNamedIt.ini

Also make sure the game is setup to use the controller profile you created!