Hi there. I've mulled upon the idea of "crowd" control before, but never thought of it as such. Here is my idea on how to work with it.
Combine Endgame and starting zones.
Think of it as a WWII theme. Newbies, fresh from training, crammed into landing boats, shoulder to shoulder with other new characters and NPC cannon fodder. Meanwhile Endgame characters are trying to capture certain points by using the landing parties to advance their own agendas via some command mechanism, and opening up content with successful advances and failures.
Meanwhile, the Newbies are thrown straight into the thick of the battle, not expected to make any great progress, and no death penalty yet, learning the ins and outs of the system while great battles take place around them, with most of the visible progress in the never ending fight being made by the endgame characters either grouped together raid-style, or orchestrating the fight through quests and NPC's.
After a perscribed amount of level, usually the point in which the threat of death penalties kick in the newbs finish their "tour of duty" and go home to where the mid level content is, and level up through regular means, with a slow build toward returning them to the fight as experienced Endgame commanders, putting them back in the thick of the fight, now commanding and affecting the endgame on a more immediate scale, now with serious consequences for failure and larger goals surrounding the same pitched battles that as a new character they were only a small, insignificant part of.