Urk posted on another website's forum (How do you lazy link with the new set up?)
The real big quote that confirms the Title Update's existence:
"None of this is meant to excuse any of the missteps away, mind you. We've already got a fairly significant "postmortem" in the works. Every one of our wounded will get a thorough jab from our bayonets."
If you keep going through the thread, Urk talks more about Halo related things!
Now, the real question is why so long and why so tight lipped about it?
I think the thing is they're giving control to 343i's. Obviously going to slow down the process quite a bit. Who knows, 343i's might even be the ones to actually pull the switch and get the Title Update Live!
Not to mention that Halo isn't even their game anymore. They're done with the series completely and are working on a new project. Slows the process down as well.
Finally, I think that the Halo: Reach engine's hugely more complexity compared to 2/3's makes it just that much slower.
Whatever the reasons are, that doesn't matter. Just knowing that they're working on something to improve the experience for us gamers is outstanding!
Bungie rocks, period!