Currently, the number of weapon marks you receive for each successful hit seems to be based on the difference in level between you and the target - attacking tougher monsters gives more marks and attacking weaker monsters gives fewer marks (eventually none if your level is too much higher than the monster you are fighting). This system has a number of flaws:

1. It encourages doing as little damage as possible. As long as you are not in any serious danger it is in your best interest to fight in coward and use your worst weapon so as to gain as many marks as possible when you are low level (most obnoxiously it makes it useful for monks to fight with a shield, armor, or while burdened to lessen their unarmed damage).

2. It makes exploring safer areas feel bad. Once monsters are too weak to give weapon marks, gaining levels from them makes it harder to improve your weapon skills.

3. It makes switching weapon types difficult later in the game, since you can at that point only gain weapon marks by fighting really tough monsters without the benefit of better DV and critical damage.

I suggest basing the number of weapon marks per hit on the difference between your weapon skill level and the targets level - so once you've gained a sufficient amount of skill with a weapon you'd get no benefit from fighting weaker monsters, but you could still gain marks with a weapon type you are inexperienced with. This scheme would almost completely eliminate the weapon skill advantages of fighting defensively, and would allow easier weapon switching since you could gain your first few levels in a relatively safe area. I think it makes a bit more sense too; if you learned the basics of fighting with quarterstaves going up against goblins why do you need to learn the basics of great swords while duking it out with fire giants?