To Craft Dungeon of Voorand part II

I have been thinking a bit about how to make an interesting dungeon again. One thing I really wanted to make a key feature of my campaign, was for it to be player driven. A sue way to snap the suspension of disbelief for me is to have the world "know" the level of the players and only throw "scaled challenges" at them. They key is to have enough open doors to let the players choose what they want to do. When I look at my dungeon maps I think they are way to limited. If I truly want the players to be able to choose what to explore there has to be a lot of possibilities to move up and down! From now on when I have nothing better to put in, sitting at the graph paper with pencil in hand, I will put in a stairway. How much is good enough? Looking over some old maps, like the maps of Blackmoor castle, you'll see stairways all over the place! Tossing out some numbers I'm thinking that out of ten stairways on a level, at least three should go to the next lower/upper level and four going to stuff way deeper down. Maybe the key here is for the players to encounter a serious temptation, or choice, to go on deeper at least once a game session. I don't think the density of stairs and the possibilities of movement up and down have been investigated much in the discussions online about dungeon design. It would be interesting to know what people think of this. Please let me know if you have any links to discussions like that. For now I have been preparing stuff for my players to explore on level two, three, four and five. If that's not enough I don't know what is!