I don't know if this has been suggested before, but I would like to see a small modification on items with guild slots in them, maybe a small white square in a corner, that would tell you if it has a guild slot.
That would prevent people from accidentally vendoring them, or crushing for essences, and also help pick out end rewards without having to check all of them one by one.
I'm sure I missed out on a lot of medium/large guild slotted items because i'm too lazy to check them out one by one.
What do you think? Suggestions appreciated, or someone with cool paint/photoshop skills :P