Basically, it seems like the zombie skill curve levels out far, far, lower than the human curve does, and eventually we had players who had 6-7 years of experience under their belt. They kind of broke the game for everyone else, and now it just feels dull and tired.
I'm one of those guys who has 7 years of experience and I finally decided to retire from play at my alma mater because the last game I played in (spring of this year) the Humans totally dominated. Most of us had modded Stryfes, we had tons of cheap ammo from eBay, we organized into three fire teams who always kept radio contact, and the people who just started playing really didn't stand a chance.
Once there's a certain experience level, it's time to move to the Invitational 'servers', I guess.
But would those problems be the same if I and a few other vets went dedicated Zombie?
Would the problem be perceived the same?
Toruk's wall o' text up top is also really really good and makes me wonder how Veteran generation happens or doesn't happen within a player culture. Why have dedicated Zombie vets not kept up with Human vets over time? Why did attrition favor the squad in my environment? Could it favor the horde in any game?