But you know they're going to, so what would you like to see?
More scenarios and more races would be great. Not only mission types (rather than the collect, flame, or move here types, although from memory there were timed missions and body-count missions) but also locations as well. SH would work just as well in fortresses, large buildings, Squat tunnels (even fortress-trains), lots of places really. It'd change up the scenery nicely, and give it a different feel for different missions.
It'd be fun being a boarding party in a BFG battle, and you could have multi-ending scenarios for how well you did (not all objectives are necessary, but taking out a carrier's engines could bring in a story-blurb that some frigates managed to do a strafing attack on a section of the ship, removing half their termies from the next mission).
Enemy types add replayability, and could be fit into the system fairly easily. Different weapons, different tactics for using them, all add to playtime and enjoyment.
Mutliplayer, with people able to control teams or even single troops. The same on the other side, except spawn points could be the controlling factor.
An option to either turn-base it, freeze-time it (ala pc version) or even fps it would all be fun. Turn-based is the main play mode, but freeze-time would make an interesting multiplayer competition mode. The fps mode would just be an additional mode made for fun, not the actual game. Think of it as a mini-game, unbalanced, just for a laugh.
There's plenty of other things they could do with it, but all those ideas listed would make it great. Actually, just a boardgame translation for pc+mobile+console would work too, but there's no reason to keep it just as that.
Ooo, another idea. How did I not think of this before? If it's kept tile based, then why not a random mission generator? Easy enough to make some fairly pretty modular tiles, ehances replayability, and would make multiplayer a hell of a lot more fun. None of this "I know the map" bs. Map generator, map linker for campaigns, map editor, and nice forum/site for saved maps from players all would add a donk-load to the "I'll buy this" value of the game.