Just as the title says, and much like doing the keyword search when in the housing editor, I think it would be a nice little thing to add to the menus in the guild traders.
I'd rather not have it but instead change the UI and toggle-able or drop down options and filters.
So I'd rather there be a search option as you describe but one that allows a few different drop downs to choose from so here is an example:
Someone wants to search for Spinners pants.
Instead of typing it, the drop down would exist for a set item search.
Once selected, it offers an addition /new drop down which shows all actual BoE sets
Once selected, it offers an addition/new drop down for weapon or armor
Once selected, it offers an addition/ new drop down for weapon type or armor slot
Etc....etc
So yes I want better search capabilities but I do not want options to search unsuccessfully by typos, or values that don't exist.
This would apply to anything but the current drop downs and UI....could be completely replaced by this
-PC (PTS)/Xbox One: NewBlacksmurf
~<{[50]}>~ looks better than *501