Make double clicking on a weapon in the vehicle creation gui automatically place the weapon on the vehicle; rather than having to drag the weapon into the slot. (whilst still retaining the option of dragging it into the slot as normal of course.) It would be a nice feature to have for when you are in hurry to quickly customize a heavy tank and get it out of the VF quickly in emergencies. Obviously the weapon grouping/mouse button assignment would still have to be done manually. This would be something for the new GUI I guess as there is no point working on the old one.
Just putting this out there as a note to myself, it'd also be convenient to allow direct swapping of components, e.g., having Plain armor and being able to replace it with Regen by directly dragging Regen over it, instead of having to drag Plain off and then dragging Regen on.