Over the years, too, other addons have been built into the game. LoseControl, for example, which I covered back in an early Blood Sport, was baked into the game back in patch 5.1. And the PvP UI is grabbing various other UI elements, from BattlegroundTargets to timers for base captures. The PvE UI, though, seems to be stagnating somewhat. Is that just because it is not in need of any additions?
One thing I'd love to see baked in to the default UI in a more user-friendly way is VuhDo, Healbot or Clique, depending on your personal preference. Yes, you can do what these addons do with mouseover macros, but man, it's hard work to set that up. And complicated, if you don't know how macros work. So adding in something along those lines to make raid healing a slightly easier task might be a smart move. What do you think? Addons that should be built into the game, for PvP or PvE... go!