I had to dig a bit to find out which recipe(s) you meant, as you're not specific. I'm assuming you mean sandpaper, as the other recipes that require sand take full bags.
It would take some refactoring and rebalancing (difficulty, yield, other required ingredients, etc.) of the recipes for the bags to be used instead of the individual bits. The first thing I ask before fixing things like this is: Is it really broken? I'm not sure it is. Breaking up a bag into bits takes time, yes, but speed of crafting is among the factors in craftng balance. Consider that one bag of sand is enough for several attempts at sandpaper and that quantity can be obtained (potentially) but putting a shovel into the ground a single time.
As I said, I'm not sure it should be fixed, but I'll give it some thought.
Splitting bags of sand like potions are vastly different things, however, because a stack of potions is a stack of potions, whereas a bag of sand is not a stack of bits of sand. As NWN works, the bag of sand would have to be made stackable, but then you'd still have a stack of bags, and not bits. Alternatively, digging sand could give a stack of bits rather than a bag, but that introduces other problems, namely a refactoring of recipes that utilize bags of sand and possible conflicts within the CNR harvesting code. It is analogous to loaves of breat or meat roasts, in that one is not separating a stack but actually converting one thing into another. In any case, it's not a simple change, and not likely one we'll look at doing.
As for the action queue and lag...it's no worse than people spamming drinking and eating. The queue causes the actions to be spread out, so they're not all happening at once.
