Wetdogeared, I'm mostly with you. If we consider the Karma as a "big kiss on the cheek with red lipstick", I guess it's useless to tell the people "Hey, look at my cheeks! I have MANY kisses!". At least it doesn't feel right to me.
What I also see is, that people don't actually brag about their Karma. It's always other users, who congratulate them. And with more and more people having 1-2-3-7-10k posts Karma tends to grow really fast

So we have a bit of a very good intentional flood.
I would lie to propose something radical. Only the milestone "owners" should post here, as first post. I mean:
LCF: I have 500 posts!

Member X: congrats!
Member Y: yeah, well done.
...
LCF: thanks
and not
Member X: hey, LCF has 500 posts.
Member Y: congrats!
...
LCF: thanks
I see some flaws in this idea, so here are a few additional suggestions:
You can congratulate X if X has already posted somewhere, that he's achieved a milestone (like me in the "what are you doing RIGHT NOW" thread.
Or, when X hasn't posted, but you know him/her (as) well (as you can know someone on a forum) and you know he/she has achieved a milestone for him/herself. (like building a new house, or having a kid, something worthy for this person).
I think that's all. Going back to being part of pohhbear_nc's assimilated.... things.