I play about 15 hours a week on average and haven't power levelled any character, save for getting them all to level 20 so I could start the end game, and I do think that there isn't much to do myself. Once I've completed the weekly milestones that's more or less it for me then until the following reset.
It doesn't bother me as it keeps me interested at least on a weekly basis but I feel they could have really done more with some aspects, like Lost Sectors - could have a procedural dungeon type mission with a strike level boss at the end - Flashpoint could have been more than complete 5 or 6 public events. There could have been some objectives to achieve as part for it for example.
They do have a good starting base this time around so hopefully the DLC will bring improvements
The weird thing is I think they made it too easy to get to 20/265 in the base game. Basically everyone outgrows the content too quickly. Lost sectors are dull because anyone can solo them now with little danger. Would have been fun if I didn't level so fast.
I'm not disagreeing on content, but 15 hours per week for a game? Some games themselves only last 15 hours total.
For whatever reason right now Bungie has not turned this into a massive time sink game. That may change in the future but it may not. Bungie could easily have added random things to grind, but they purposely took those out. Not saying people should like it, but that's the direction they are going.