It IS quite interesting that the Warhorse is more effective for the Wizard than for, say, the Warrior...
I was actually playing the Knight character, which made it to me, fall more in line than the Merchant who was actually using it.
A question: what about the Monk? Can he add his Craft value twice if he has the Warhorse?
THAT is an interesting question. I guess my answer would be YES, because otherwise, the only bonus a monk would receive from gaining the warhorse would be saving 1 life.
The Warhorse has never made sense the way it is written. A warhorse is trained for battle, requiring some skill in using such, but having intellectual prowess isn't what's involved. And the whole thing with Craft / Psychic Combat is out in left field. Better to house rule that the Warhorse allows +2 when Attacking but not when being Attacked. If you lose a Physical Combat, lose a life or the Warhorse. That's the way it would really work.
I have 2nd, 3rd, and 4th Ed. I remember from 2nd ed, it specifically stated "charging" into combat, and that word alone caused a major problem - i.e. "What is charging, can you charge on board encounters, or when you are attacked," etc.
I would say it needs to be worded as: "Add you starting craft into your strength for any Enemy or Character you attack, but not when being attacked."
The +2 takes the advantage away from persons with higher craft, but at least your way, it is clearly worded.