A post to the BeyondUnreal Forums that BeyondUnreal says is from Epic's Steve Polge indicates the major patch plans mentioned today represents half of their planned Unreal Tournament 3 expansion, to be followed by "the Titan Pack" that will add all sorts of goodness that they are not revealing just yet to their shooter sequel:

We've decided that the best way to deliver the UT3 expansion we've been hinting about is in two parts. This patch is the first part. We aren’t quite ready yet to start going into detail about the bonus content and gametypes that will be in the Titan Pack, which is substantially bigger than any bonus pack we've released in the past.