Sorry to hear you feel that way, Jason. I can definitely see where you're coming from, though I actually feel just the opposite. For me, a game quickly becomes stale when I don't have stuff to work level up and goals to work towards. It's why I have trouble using a maxed out weapon and why I always have to hit the prestige button...the game doesn't feel complete if I'm not working towards something. Not having people to play with regularly, I was about as high as I was going to get, but now the DLC brings new stuff to level and new goals to reach for.
If I'd put as much time and effort into the game as you guys have (I wish I could have!) maybe I'd feel differently, I don't know.
Anyways, if you ever feel like taking a trip into the old Vault I'd be honored to learn its secrets from a master such as yourself.