Before AFCI's I generally ran all receptacle circuits on 20 amp circuits and lighting circuits on 15 amp circuits, still do and hasn't forced me to change much. I might put a few more receptacles on a circuit than I used to, particularly in living rooms, bedrooms and similar areas but that is about it.
More efficient lighting in recent years is also making it so there is more lighting outlets on one circuit than there maybe used to be.
I don't know why you would want a heavier load on your receptacles to dim your lights, and even worse effects with some the LED's these days, keep them off the general use outlet circuits as much as possible IMO.