this is not true,
both sides actually have quite a nice amount of players.
its more to do with organisation on the night, and self organisation of individuals & thier actions after the game/s (i.e. some people /afk just before the game ends so they dont get a loss on thier score card, and usually killing off that side's que population and ending that night's games)
so to be honest it really doesnt matter which side you make a character on, but your best bet is to make 2 twinks, one on each side.
my reasoning being that we might find ourself in a 6v10 situation one night, and then some people in the 10 can log thier characters of the opposite faction and make it an 8v8. if you see my point.