if you do go the stars/dots route, suggest you get them all done at once by the same tattooer, so they look consistent. and a tattooer that is experienced with that traditional look.
but idk, perhaps just leave it. adding dots/stars could really muddy it all up, i'm not sure if it will really 'bring it together' - your pieces are all black and they are already fairly close together.
you still got room for a nice wrist tattoo and what looks like a lot of torso real estate for some really cool big interesting pieces. that might help you take your own focus away from feeling your arm is incomplete (which i don't think it is, looks great as-is).