Mucking with Combat Returns

After thinking about this post from yesterday a bit more, I've come up with a quick and dirty attack system:

-Characters divvy up a base attack progression between three attack types, Power Attack, Relentless Attack, or Finesse Attack. There are also corresponding defences of each type.

-The base attack progressions range between 1/1 (+20 at 20th level), 3/4 (+15 at 20th level) and 1/2 (+10 at 20th level) and what slots are available may vary between classes, possibly, maybe.

-Power manoeuvres are modified by Strength or Charisma. Relentless manoeuvres are modified by Constitution or Wisdom. Finesse manoeuvres are modified by Dexterity or Intelligence.

Now for the part where there's actually a point to this...

-Each attack has a strong or weak defence; it will do bonus damage against a weak defence and less damage against a stronger defence, but standard damage against the same type of defence.

-Power attacks are strong against Relentless defences, but weak against Finesse defences.

-Relentless attacks are strong against Finesse defences, but weak against Power defences.

-Finesse attacks are strong against Power defences, but weak against Relentless defences.

I'm not sure who bonus damage should work out quite yet.