Simplified weapon mastery system for heroic games (?)

I’ve been working on this simplified Rules Cyclopedia style weapon mastery system, and I was wondering how people here think it would work for a heroic fantasy type of ACKS game, for beefing up and cinematizing weapon combat.

The gist is contained in this table:

Mastery Level - Benefit
0 - Nonproficiency penalty
1 - Proficient
2 - 1st weapon special ability
3 - +1 to attacks and damage
4 - 2nd weapon special ability
5 - +2 to attacks and damage

with the individual weapon special abilities outlined on the blog (most of them taken from the Rules Cyclopedia, like entanglement, strangling, stunning, and deflection). Everyone gets level 1 mastery in their class weapons, and fighters gain an additional 4 slots at 1st level, thieves and clerics 2, and mages none; characters gain an additional slot at each odd-numbered level, and can have a level of proficiency equal to their level +1.

I figure it’d just be a bolt-on system which would stack with fighter damage bonus, fighting styles, etc.

The system in the blog has d6 weapon damage rather than variable, and gives einhander fighters a +1 to saves to balance it with the other styles. You can ignore this stuff if you don’t like it, since I’m mostly looking for thoughts on the mastery system itself.