Kensai is better at lower levels, but I think you're right, the fighter comes out on top in the long run.
The extra THAC0 bonus is good in the early stages of the game, but even so IMHO that never balanced out the fact that you couldn't use armour or ranged weapons.
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Time is an illusion. Lunchtime doubly so.
Epona of The Laughing Hyenas