The reason you are having such a hard time finding group for heroic quests is simple - you were in Early Access and now you are too far ahead of the majority of the leveling crowd.
Do a /who on your level range, then a /who on Coruscant, Taris or Nar Shaddaa. The numbers themselves should tell a clear story.
You aren't speaking for me my good sir.
I'm talking about going back to the previous few planets when the quests are green.
Its very easy to see how many people are on planet. It is not a matter of not having the numbers on planet to do the quests, its a lack of interest from the community.