It will be interesting to see what Mongoose do with the T2k idea - First edition was not really a post-apocalypse game, but a military game in a post-apoc setting (All characters were military, no real guidance on using civilian skills to rebuild - how long does it take, what materials are needed etc), and was actually a fairly brief game (1 24 page and 1 32 page rule book, plus some charts and the equipment book). Ed 2.0 and 2.2 allowed for civilian characters, but still seemed biased towards PCs being military. T:2013 did a much better job of providing for a range of character backgrounds, and provided a much more comprehensive coverage of natural hazards and rebuilding/civilian type activities (and took >300 pages to do it, including equipment lists).
One of the strengths of T2k was that it was contemporary/near future - everything in the game really exists, or is at least a reasonable guess at what might be developed, even if GDW got it wrong. Similarly, it's a 'hard science' post apoc setting: there's radiation and disease and bad guys with guns, there are not mutants or zombies or aliens or killer robots - it's my world, only broken.
So what would I want in a new Mongoose edition?
i) A setting 10-20 years into the future, with the "bad thing" that caused the apoc to have lasted a few years, and be coming to an end: I find T2k to be hopeful to a degree, since the war is ending - rebuilding can now begin and things can start getting better; the T2013 background less so, since the apocalypse is really a whole series of events which are still ongoing.
ii) Real technologies, or sensible extrapolation of what currently exists.
iii) The same sort of comprehensive coverage of environmental hazards and rebuilding that T2013 featured.
iv) A bias towards military based PC groups.
v) A workable small skirmish system, so that the PCs can lead/support 1 to 2 dozen NPCs against a similarly sized group of bad guys.
vi) Properly researched stats for the equipment included (GDW got a few things quite severely wrong, for example armour levels of FV510 Warrior: see here for details http://rpggeek.com/filepage/55444/fv510-revised-and-updated-armour-values , if you don't mind indulging me :wink: ).