The 58 boost starts 75% of the way into the level and fully rested!! That means you have almost no XP to gather any gear, all serious level 59 twinks will have to level from scratch. 69 twinks will be more active I'm quite sure, more people will be completing the journey from 60-70 and thus Quing for a side game here or there, which is something you need to keep a bracket alive and well : )