What matters is not that you get an extra free action; you get that with the quality no matter what, and you can take the quality WITH Rapid Draw. What matters is that rapid draw lets you attack as a free action. Without it, you can only attack as a complex - which removes your ability to use simple actions.
This in itself can completely fuck up the action economy and tilt the whole argument against guns.
Free Actions (shadowrun 163)Free Actions are relatively simple, nearly automatic actions that require little effort to accomplish. Examples are saying a word, dropping an object, gesturing, or walking. A character may take one Free Action during his own
Action Phase
or at some later point in the Initiative Pass. A character may only take a Free Action prior to his first Action Phase in the Initiative Pass if they are not surprised (see Surprise, p. 192). Only one Free Action is normally allowed per Initiative Pass, but multiple Free Actions could be allowed by the gamemaster if the situation seems reasonable(dropping an object and speaking a phrase). Free Actions generally require no Success Test,though special circumstances may warrant one.
Throw Weapon (page 166)
A character may throw a ready throwing weapon (see
Ready Weapon, p. 165) by taking a Simple Action. The
character may not take
any other attack actions in the
same Action Phase. Multiple readied throwing weapons
can be thrown at a target within Short or Medium
range by adding a Multiple Attacks Free Action (see
Multiple Attacks, p. 196).
It seems to me off putting that you would be better then a gun man at ranged with your shuirken, because you mess up the action economy: your action phase: ready throwing weapons, throw weapon (save your free action)
in your enemy's action phase: you know what free action: ready and throw another shuriken/grenade before he gets a chance to act (or at the same time)... I mean I like boosting something as adept just like the next guy

, but if rapid draw is that good, why waste it on your own turn, where you already can attack normally, no do extra damage on the opponents turn.... It gets outright ridiculous if you use a motion sensor grenade on your opponents IP.