Congratz on #1 . But i think F2P has nothing to do with it. (And that's because there isn't only 1 leaderboard/server in game)
One easy way to reach #1 is start new account, If you are IoS you have Poe, so you get droids. Skip daily missions so you wont advance fast in level.
If you stay as low level as possible, you ll be in the lowest servers in arena, with people that just starting the game. And with droid team its a fast ticket to #1. Don't care about skipping dailies. You get much better rewards for being #1.