Myrrh, Frankincense, and Steel: Kurald Galain's Guide to the Magus

[Kurald Galain]

A weird thing is sticking VMC Fighter to a Kensai.
Armor Training will allow you to use armor without being proficient, but the new advanced weapon training options will now be availlable for a kensai, too.

Wearing armor gives the kensai arcane spell failure; VMC fighter doesn't mitigate that.

See, canny defense isn't there to give the kensai better defenses than an ordinary Magus; rather, it is there to compensate for the fact that he can't wear armor. It's probably better to cover your defenses with Mirror Image and Displacement spells.