I know this is going beyond answering
Iron Budokans' question, but I have to give my opinion.
I agree that the whole fatigue model in SH3 is messed up, but I also feel that it's strange to play without it. And I actually enjoy the added issue when things get crazy. But I hate dealing with it when I'm cruising around. My solution; drop the 3D model down to 16x with SH3 commander and play with the stock GWX fatigue.
This solution, I feel, allows fatigue to become an issue (which it should be), but not the overwhelming issue that it was. Plus, you no longer have to manage your crew unless you're at less than 32X in attack or getting attacked.--which makes the experience more fun for me.
Whatever--enjoy the game however you want
J