With regards to this specific set, I'd buy four or five as-is to support the concept (because it's a brilliant idea), but the bases leave me cold at the moment. They're useful, but I can get ones like that elsewhere, and I'd prefer more infantry than bases, personally.
I realise that this is a 'concept' sprue rather than a final one, so if you're open to tweaks and assuming you're keeping the bases, I'd vary the hole placement on them for variety, and I'd love to see them incorporate subtle ruins/rubble/craters/texture.
I'd like a greater variety of poses in the infantry – some kneeling in particular – and I'd prefer machine guns to missile launchers (or perhaps a mix?)
I'm in two minds about the vehicles. I think I'd like a sprue that concentrated on APCs and infantry, as those go well together. As it stands, the inclusion of APCs, artillery, tanks and infantry makes it seem a bit unfocussed. I rather like the suggestion of multipart tanks to increase the detail, but ultimately, I'm simply not that fond of the artillery or tank designs, which is probably what's tipping me towards wanting more infantry and APCs rather than the other bits.
A little bunker, gun pit or section of trench line would be cool if there's space. Would it be possible to design the sprue frame itself to be textured? If so, perhaps the bases/trenchline could be incorporated here?