You have recreated an addon that combines functions already available in grid and other raidframes and a quckheal-esque addon into one?
I don't see how it would be any less resource heavy than others because there is only one way to check a 40yard range inside in vanilla and that is with IsActionInRange..
the basic idea of this addon is to have a tool like ctr-health monitor/ rdx / healerassist etc...BUT super easy to use - no config need at all, super lightweight and fast(atm it takes 0 resources with normal 28yrd range scan), no uber-big UI
this addon doesnt replace a raidframe, but its an additional tool like RDX, it has some benefits and functions compare to all the other health monitors thou..
the autoheal function is just a bonus and req. CM, bonusscanner and lazyspell - its something i included, but noone needs to use it - ALL healing technics are allowed (targeting, CM, clique, lazyspell)
quickheal chooses not even ranks but also the spell for you, wich is imo pretty annoying and different from my addon
about 40yrd range: yes i check it with IsActionInRange, this req. a 40yrd healing spell in action bar - atm i have a refresh freq. of 2 sec, wich can be changed in option menu - i already had a bugfree raid with 1 sec. refresh rate