I think the full load certainly would have to include all the unattended loads, HVAC, water heater and a certain amount of the general lighting load, maybe the range and dryer. The first 2 are the killer. If you could put a smart box in front of them similar to the PoCo energy saver that required manual restart if on generator power you would go a long way towards making me happy about 702.5(b)(2)(a).
If you are doing a load in the washer (water heater going, 23a), a load in the dryer (23a or so) and have something on the stove that alone would overload a 12KVA generator and when the A/C kicks on you got trouble right here in River City.
I do think a simple interlock that trips out these big, discretionary loads on the transfer would be a solution and you can let the user do load management by manually turning them back on.
