an algae scrubber will out perform any protein skimmer and make for a healthier tank! and with very minimal water changes!!! unfortunately a reef aquarium does not have the needed environments at the correct ratio liek the ocean to provide enough to feed your corals and other animals in the tank. they will definitely survive, but to thrive i think its pretty excepted corals should be fed.
and about your concern of light being blocked by too much in the water. studies have been done that show most corals will get much much more out of food than light and will consume as much as possible, they digest as fast as they can eat. your only concern with putting food in the water should be about what it does when it breaks down. culturing your own phytoplankton would be perfect for you think, since it will stay alive in your tank and can be added in higher concentrations and more often than most other coral foods.
all in all, feeding coral takes minimal effort and is definitely worth it.