I have given this matter some thought, wondering what makes a kensai. Well, I figured a kensai strives to be the best melee figher ever. To excell in one particular weapon. To be the best fighter ever that person needs to be very focused and determined (high int). A trained body to endure the battlefield (mainly dex, con and perhaps str).
After many hours of pondering the matter I came to the conclusion that a TRUE kensai would never touch magic. That would be cheating and not portray the true skill of a swordsman. Thus a TRUE kensai would never use any magical items (except potions since I don't consider them magical).
The problem is that a kensai not wielding magical weapons is soon a dead kensai.
I think a TRUE kensai should have the same attributes as a Monk i.e. to be able to hit monsters "hitable" only by magical weapons and not able to dualclass. Like a mage they live for but one thing. But, well, it is not done like that so... In my opinon there is no kensai in BGII, just a kensai cheese kit.
And no, a monk is not a kensai. A monk is driven by a philosofical/religious cause,
I have a kensai in my multiplayer party who I will later turn into a kensai/mage.
My reason?
My kensai wants to be the best fighter ever. After a while when the kensai gets more experienced and see's more of the world he/she will get to know magic. With magic a person can be invulnerable to both melee and magic.
My kensai in thus no TRUE kensai. I want to use the Celestial Fury for one thing and if the goal is to become the best fighter ever I believe a kensai would use magic. Wizards also needs to be very focused and determined. The diference in attitude is not to far apart.
Your "excuse" for playing the kensai/mage?