Yeah, magent type and wire length (number of turns) are the output variables. More wire (= more turns) give more output and more magnet gives more output.
This is why DC resistance is given as a rough guide to the power of a pickup: its an estimate of the length of wire and the number of turns (as the resistance is proportional to length). But as Eric and dave rightly say, the thickness of the wire affects its resistance, so you can have alot of turns of thick wire at lower DC.