I have this problem. Have WD40'd them a few times and one has improved but the other hasn't.
I've found that the more the handle is used, the better it gets. I always open the rear driver's side door to let my daughter in the back, and to lift my bag for work. The handle on that door is gradually getting less sticky the more its used, and can now close by itself, though it still sticks out a slight amount.

I haven't got round to taking the doorcards off yet but may do this weekend...