By the definition of 'complete' that you have been using, rolling 1d20 and beating 10 for any given action is 'complete', too.
One thing is covering, another is covering in a satisfying way. When my efforts at creating a unique and interesting character have no actual effect, I am not satisfied.
As for the reason for which I am posting to this thread: the original poster wanted to know our experiences with rules-light systems.
My experience is that, unless you are content with a very poor mechanical representation of the game world, it takes so much effort to make them work, that I'd just learn d20 instead.
I have all the respect for people who like rules-lite systems, but personally, when I ask something to the DM, I won't take "you can't" or "it's the same as a normal attack" for an answer more than once or twice. It makes me feel as if I was playing Monopoly. I'd rather play a rules-heavy system and not know the rules - at least I have room for improvement.