I than started looking around and noticed that Light had the 30% hp/dmg flag while Darkness did not This seems a bit massive considering the diffirences. Their creeps have more hp and do more damage thus making them harder to kill, this becomes more problematic when the game progresses to cata's and giants.
If light had their flag, and darkness did not have their flag, this means that I assume) light had both. This means not only is Light 30% + 30% better, but Dark is 0% better. That's a gigantic difference, and is wh ,yes, flag and mao control is very important.