Light level mmm, what if we have Dark levels as well? I mean, yin and yang, black and white, traveler and darkness. Why not let players choose their path like in KOTOR? If you choose Dark Side (insert star wars pun here) you can level your character to level 30 as well, but with different armors, probably looking more menacing and with different perks. Possibilities are endless, new missions that require you to have certain amount of dark level or light level. Weapons can deal different damage as well based on your light / darkness level. Of course this could happen after the story develop with time, when the traveler reveal itself as the enemy, or whatever crazy idea came from Bungie.