Since DDO makes having lots of alts easy its sometimes hard to remember / tell who a particular character belongs to - be that in guilds chat, guild listing or elsewhere.
I would like to suggest a very simply addition to the game - purely cosmetic - which should make this much easier.
Allow each account (not each char but each account) to type in a nickname. Since my real name is Jan and we use our real names in voice I would probably set my nickname to Jan. Lets say I have the characters Mikarto, Smeden and Flyttekassen. From those names nothing shows that they are all mine - but lets instead use Jan-Mikarto, Jan-Smeden and Jan-Flyttekassen. Use those "names" in text chat, guild listing, group/raid list etc rather than Mikarto, Smeden and Flyttekassen and make an option to toggle between adding the Jan- or not.
That would be really great imho - and since its all simply text strings in the UI it should be very easy to code as it simply replaces the "Name" with "Nick-Name" everywhere.
To be truly usefull nicks would need to be unique within guild.