Certain mission planners garner more pilots...plain and simple.
Ripsnort comes to mind for the Knights. Al he has to say is "Mission up" and boom, he's got all the assets he needs.
Why? Repuation. Rip not only builds well thought out missions, he LEADS them. Execution is just as important as planning. From target assignments, to flight leaders, etc, Rip, and a few others, control the mission from start to finish.
Other's who I've flown with, throw a mission together, and even if the strategy is there, the planner, just flies off and leaves the mission pilots to their own resources.
The there's the third type, who does none of the above and then whines when there is a low turnout and the mission fails.
I keep a short list of people, who's mission's I would never fly because they just don't lead them.
Build a reputation as a leader, and the pilots will join.