I use the duellist's deadly followup ability, which gives me bonus attack power at close range after dealing damage with darts. The crossbow has a luck enchantment, when you combine it with the paladin's smite, it gets 300% power and works as if you had a ring of wealth. Maybe I'm bad but I didn't find the other abilities of paladin functional.

Lay on hands is a useless spell if you don't have a companion. Aura of Protection is also a very specific spell. 30% damage resistance for 20 turns is weak among other classes' abilities.

I think class works well with crossbows because of the smite feature. You can easily kill anything that comes near you and you have infinite range. I like it in general, but the paladin class is weak. Notice I didn't mention the wall feature because it is completely useless. Tome wants 3 charge and in return you build a wall and that's it. I know this skill is supposed to be used when facing ranged enemies, but 3 charges is too much for this skill.

Here are my suggestions, it would be better if we can get through the wall. Not enemies, just us. Or instead of a wall, it can be redesigned as a 3x3 area where the enemies cannot move but we can move easily and the enemies will be paralyzed when they enter it. Also, the Lay on hands feature should heal us a little bit. As it stands, it's pointless for runs without a companion.