Use some free keyboard mapping software and assign the keys you want to WASD. Why the changes don't work, I don't know, I experience similar things in other games and just use mapping software instead of trying to figure it out. In some games the camera pan keys are hardcoded (usually to num pad), you can change it to work with other keys but the original keys can't be assigned to do anything else, they still do their original thing. That may be the case with this game, I never tried to reassign those keys before (I did reassign the camera rotate keys and that worked). My favorite game, Supcom, you cannot even reassign the camera pan keys and that game was made around the same time as this one and it drove me crazy for awhile. My keyboard has mapping software though (Merc Stealth) so I have no advice to give on what free software is best, they all work though.
You can try putting your preferences/settings file to read only, worth a try.
The FPS view kinda sucks in vanilla since the ground looks so crappy already and seeing it from such an extreme angle all the time makes it worse. In my mod I updated the ground textures, lighting, and replaced all the grass, might want to check it out if you want to use the FPS view all the time.