TL;DRInstead of allowing the player to hand-craft while moving, the player should have to stand still in order to hand-craft.
What ?Currently, it is possible for the player to perform hand-crafting while moving. I am suggesting that the player should have to stand still for several seconds in order to unpack his hand-crafting equipment and to remain standing still for the actual hand-crafting. As soon as the player moves, he stops hand-crafting and will only continue hand-crafting after he has been standing still for long enough to unpack his hand-crafting equipment again. So that the player can better understand what is going on, an animation should play when he is unpacking his hand-crafting equipment and a different animation should play when he is actually performing hand-crafting.
Why ?Currently, if the player urgently needs an item to be hand-crafted, he must cancel his entire crafting queue in order to craft that urgently needed item. For this reason, it has been suggested many times that it should be possible for the player to be able to insert items to the start of the hand-crafting queue. For example, this has been suggested in the following suggestion threads:
viewtopic.php?f=6&t=62338 Double ended crafting queue
viewtopic.php?f=6&t=49361 Rearrange hand craft queue - QOL
viewtopic.php?f=6&t=41594 Ctrl+click to add to front of craft queue
viewtopic.php?f=71&t=63092 Reorder crafting
viewtopic.php?f=71&t=63175 Please reverse the craft queue
viewtopic.php?f=6&t=63560 Crafting Priority
viewtopic.php?f=6&t=23453 Modifier key: in-hand craft in *front* of queue
This suggestion has been declined by the Factorio developers. In this post, Factorio developer Twinsen states that the hand-crafting interface is supposed to be annoying, because they don't want to make hand-crafting too powerful. They want people to automate instead.
I agree with the Factorio developers that hand-crafting should not be made too powerful, because the goal of the game is automation. However, discouraging hand-crafting by deliberately having an annoying inflexible interface does not seem the right thing to do. In my opinion, there are better ways to discourage hand-crafting, for example by requiring that the user is stationary in order to hand-craft.
In other words, I fully agree with Twinsen that hand-crafting should be annoying, because the goal of the game is automation. I just disagree with Twinsen about how hand-crafting should be annoying. Instead of making the interface annoying, the game should make hand-crafting annoying in a way that fits better with the game. I believe that this is what my suggestion accomplishes.
If my suggestion were implemented, then hand-crafting will be sufficiently nerfed, so that there would no longer be any reason not to implement the priority hand-crafting suggestion mentioned above (and also other QOL improvements to the hand-crafting system).
EDIT: updated the list of suggestion threads