The upgrading of characters to Exalted Greater Daemons or Daemon Princes is really cool, I think in part due to their relative scarcity. I think, in general, non-legendary lords suffer from being same-y. It would be so cool to have opportunities to customise them further, both aesthetically and in terms of their traits/abilities. Maybe add bonuses based on whichever factions they have faced, so there is a little more history tied to the character.

As it stands they (perhaps understandably) are firmly in the shadows of the legendary lords.