We already have the route, so both these locos as a DLC set (with Mk2 coaches) would be an absolutely fantastic addition imo.
I wouldn't mind seeing these as part of a back-dated London to Brighton route, we desperately need some slam-door EMU stock.
A pack featuring these sets as well as 4VEG, Class 460 and 442 would make a great 'Legends of Gatwick Express' add on. This is pretty much the complete line up for Gatwick services from the start to just before the 387s showed up.