Ok, I've been playing a while now and while GAR does generate the new player every once in a while, I believe the growth rate could improve with 1 simple idea.
What I have noticed in chat or in game when new players begin playing is they feel like most people are using some kind of cheat because their weapons seem way over powered, or they simply won't die like they should. We have all felt this at one time or another. The problem is those "super robot" players are usually just decent players who have honed their skills and builds and 99% have 10% guild buffs making them seem like they are using some kind of cheat in the eyes of the inexperienced player and that is why I see a new player for 2-3 days and never again.
So, simple solution. Give players incentive to want to rank their robots up. The problem now is, and I speak from experience, is once you reach a certain rank robot, the gains from each game are almost nothing to even it costing you coins to play that robot per match. I believe if the Dev's can incorporate a ranking system in rewards according to robot rank this will solve the issue of everyone wanting to be rank 2 or 3 giving the new players a little room to get to know the game we have all come to love.
Other incentives could be implemented as well, but the reward per game is to me anyways the thing that keeps me from ranking up a robot.