Good idea, indeed.
My game - for a small comparision - is divided into stats, attributes and skills, based off games like Fallout. There are 5 attributes: Strength, Endurance, Agility, Willpower and Intelligence. Stats are things like HP, MP, speed. Skills include lockpicks, barter, combat skills, magic and some miscellaneus ones. As you start game, you get different attributes for various characters (perhaps I'll change it so that you can add points to them yourself with certain class limits).
Beside items, you can't change stats, but they improve depending on your attributes. For example, having a few points of strength will give you thing like +15 HP each level, but having 10 strength will give you, let's, say, +50 HP. So characters evolve during gameplay, depending on your profile.
Skills can only be improved by adding points to them (gotten after level-up, amount dependant on your intelligence), so that they gain higher levels - the higher level, the more points needed.
Personally, I don't like mixing stuff like HP/attack with things like evasion etc... But that's my very own personal opinion.