I have been considering what you are speaking of. Thing is, masteries do not need to be fully positive all the time, like in the case of double edged sword for example.
Adding this effect as an item or an effect attached to an item might solve the phase problem which you pointed out, but then there is another problem about picking said item without considering this effect because it' s worth gold-wise or not picking ir because, even with this effect, is not worth goldwise. The usual problem about power vs utility, somehow.
Adding it as an enchantment for boots would make it pretty much mandatory in some phases of the game, but also it would make it very sustainable to build. Probably too much.
Your concern about point and click abilities is valid, but i am not too much afraid of that - is stuff that will always be looked for since it's very strong of its own. I am worried however about its effect against certain compos, since i like to think about masteries more as something personal rather something dependant on the battlefield, lile body-stopped skillshits and point and click projectiles.
Then again, this is supposed to be only a kickstarter proposal to start off a discussion. If you don't like this, can you tell me about a version you would like to see more, or at least explain why a thing like this is faulted at its core and should not be present in the game?