I would also like to have a way of switching between simple weapon sets (e.g. weapon + shield). It would still cost the same amount of AP as now (sum of both actions). But it would be a convenient way to change from a 2H weapon (like bow) to 1H + shield. So instead of doing it in 2 steps you could do it in 1 step (yes I'm lazy

).
I think it's easy to implement this using the current quickslot system. A slot could accept both a 1H weapon and a shield. Using this slot would equip both the items, given enough AP available. If there are available AP to equip only one of the two items then the slot would be disabled and the player would have to use another slot, with only the weapon for example, or the inventory.
Also I agree that the carrying capacity/weight of items feels somewhat imbalanced or not logic. Either some of the items should weight more, or the weight limit of the characters should be reduced. I think this is the first game where I haven't been *over-encumbered* once yet. And I generally tend to carry a lot of crap