[quote=@Rilla]
Why only subtract 30, if you dodge?

Perhaps a attack-defend roll, with dodging to power damage?

Perhaps; 

attack for 100%, defend 75% of that and then the dodge roll be to whether or not you avoid it entirely, depending on the mechanics. But I've never been a dice man, when it comes to actually making a system
[/quote]

Even if they have 100% base accuracy, with the enemy having 30% dodge that reduces you to only a 70% chance of any hit at all. Which I guess is still not bad but for things liking shooting fireballs and stuff you wouldn't start with 100% anyways.

I prefer a roll to hit and then do damage based on the attack power of the attack.