Just though it was interesting to note that DOOM II has been released on Xbox Live after quite some time from seing it at PAX 2009, the interesting thing is this:
When you start the game, the copyright notice reads 2009.
And, prehaps the most obvious change : the Healthpacks and Stimpacks in Doom 2 have been edited to have the 'Red Cross' removed, instead being replaced by an image of a pill. most possibly Nerve Software did this after the recent whining by the Red Cross that the cross was their property and should not be used for anything non-related to the organization.
Surely the delay in releasing this game can't be because of the Red Cross...
I've added an image of the health packs before and after (taken from my phone so excuse the quality if it is not too great, old original is on the left, new XBLA is on the right)