Or perhaps a mission model that does not involve conquering pieces of the map, allowing focus on more story oriented missions (missing 'parts' of the first Tiberian War history) Introducing them into a direct remake of TD would probably upset how the campaigns are planned out, so instead I would suggest that some kind of 'side quel' is made or a kind of expansion pack, a companion to Tiberian Dawn that takes place during the war but in parts of the world not depicted in the original game United States, Russia, South America, Asia, Australia etc.
I have been thinking a lot about what I wrote regarding change of unit looks and introducing new units into Tiberian Dawn.