well last time i made a major warring nation - i had lots of members. last time i made nations with intentions of winning set - i had lots of members (Smile, WAL, DaK). those are the 2 causes i have. enough people always turn up for them.
i think you still dont get round the concept that i dont have time to do similar set ups like other nations...when i have desire/time to do something big - i recruit lots of ppl. when i dont - i scale down and ask only ~ 3-4 people (same ppl each time) to join.