They should upgrade what they can, without further delay. Letting the value proposition sink for 20-22-24 months, damages the brand.
What could be easier than adding BTO options for more RAM? It takes a few taps on a few Apple employees's keyboards.
I am sure you're aware that the MBA memory is not DIMM-based.. the memory is soldered onto the motherboard. So adding more memory would entail a motherboard design change.. certainly would not be a BTO option.
Personally.. I wouldn't care for another minor C2D based refresh.. Apple needs to figure out how to move MBA to a modern generation processors (be it by Intel or AMD). They also need a form factor refresh - the current one has gotten stale. If it takes them another 6 months - so be it. Another minor C2D based update would be an embarrassment.