Dropping everyone that's currently at a high level back to lvl20 would mean we couldn't even run VoG or Crota, do Nightfalls, weekly strikes etc... so I think that's just not going to happen. Seriously, how annoyed would a lot of their customers be to have their level 34s equalised with other peoples lvl20s. I'm sure our levels will stay as they are. There will be a big xp grind to get to 40 and then new light levels to build up based on weapons, armour and probably class items as well.