I really wish that certain NPC's were able to recognize certain details about your factions, such as being the Archmage or The Listener. For instance, I am currently going through the Thieve's Guild questline after already having finished the Dark Brotherhood's. When it told me to go talk to Devlin I was surprised when he acted like I was some fresh-off-the-street-newbie, even though he should know exactly who I am, or at least have some knowledge that I am in the Dark Brotherhood.
I just feel that it would be really neat if some important characters like that were able to recognize that you've made certain accomplishments because face it, guards noting things is interesting, but just doesn't seem to cut it...
It isn't an important change, and unlikely to happen in this installment of The Elder Scrolls, but it would definitely be interesting when the next one comes out.
Thank you for reading!
-Dinvex