Dont think it suppose to be an easter egg hunt. straight forward get item then deliver.
Well, first off imagine being a new player to UO in general. I am sure the whole thing feels like an easter egg hunt until you do it a few times and notice where things are or that some items only appear on one NPC vs others that can spawn on a few different ones.
I am simply pointing out that if you get a trade order there is someone, somewhere in that region, that has the item.
In this case that miller has always been there. Yew getting a few shop changes didn't change the system you just need to look a little sometimes. Now that you know if you got one similar the next time, you know where to go.