Their current complied rules update is 117 pages! Wow. So I just look at the update for the core set. It been two years since I ran a campaign in D&D 4e so I wanted to understand what I am in for if I ever ran one today. Between all three core rule books there are 37 pages!
Immediately I flashed back 20 odd years to the debut of GDW's Megatraveller. It was intended to be the end all to be all update to Classic Traveller. However one thing that brought it down was the sheer volume of errata to fix broken and misprinted rules. Not just little rules but needed changes to fix the combat system.
I also went through similar experiences with Star Fleet Battles and Battletech. I can tell you it is a source of frustration and a barrier for new gamers playing for the first time.
Bob: What do you mean it doesn't work that what?
Alex: Yeah it was broken so they changed in the errata here.
This is of concern because if the mainline RPG (D&D 4e) sneezes we all catch cold. I really hope that Wizards doesn't have to do this with D&D Essentials. Because this volume of errata for any game is just a millstone around it's neck.