I know that...I'm a geanyous!
White doesn't need regeneration. It'll either protect the critter or prevent the damage.
Also, white is the color of combat tricks, anyway.
Pacify, Muzzle, Arrest, Shakles, Soul Scuptor, MoR, Festival, Holy Day, Healing Salve, Ramosian Rally, Cho-Manno's Blessing...heck, I've seen LASHKNIFE save the day! White can not be stopped unless blue says so, because blue can not be beat. Blue is the only threat to white, and blue does not need creatures 'cept Superman, and nothing can stop him, not even a white regen, since blue will just counter it.