Do Nothing makes the trigger slower, because it counts as a step, means it takes processor time to be worked on... just take the criticsm and fix the leaks and that shitty stuff.
And yes, positions will be overwritten, but it will leak, because they don't get deleted by being overwritten, they just wont be referred anymore by the location, means they are lost in RAM (lol... lost in Space), that fills your ram up, makes your pc go slower and slower with each cast.
just take the criticsm or leave spell making.
A tip: no one likes dota spells beside the newbies and those which are too dumb to see that those spells are utterly easy to create, and of course dota fanboys... which count to newbies, i think.