MIG wrote:

Will we get 12-car trains on Thameslink before we get them on "Kent
Link"?

Network Rail are planning to introduce 12-car services on all
Southeastern suburban routes via London Bridge around 2011/2012 - check
out Chapter 7 of the South London Route Utilisation Strategy.

http://tinyurl.com/2k29zc

But the Moorgate branch will sure as hell close, and
there will be huge disruption for the pointless work.

It will be pointless (well sort-of), but not in the way I think you
meant.