The problem with this is that the programmers of 3DRealms ALWAYS took a lot of time with their games ...
But they changed a hundred times of engine ... your only chance of this is they staying with their original one ( the highly modified Quake one ) instead of switching to the much powerful but horribly developed by that time Unreal one ...
The result will be a one somehow graphically obsolete game, but with a really good game playing and a lot of (politically incorrect) humor ... so like almost every game they had done to that date.
The influx of money will make them made more games, but just 2 or 3 more in all this time ( they are THAT slow ) ...
EDIT: Also DAIKATANA would never exist, so a friggin UTOPIA on Earth ...