RNG in a skill based game

I've had questions about crit chance, and specifically IE, for a quite a bit, as it seems to go against most of Riot's philosophy (as I intemperate it).

(Explaining for the sake of "hey, this is where I'm coming from") This is, primarily, a mechanically based game which also requires some ESP and practice to play effectively. There is cheese involved (and a lot of it is curdled), but it can all be overcome through the aforementioned systems and are levers Riot can tune to a degree. There are obviously exceptions to the rule, especially true for older systems, as the game is constantly molting and aging (sometimes like milk, and sometimes like wine).

The exception that most blatantly comes to mind is Crit strike- this enhances the dps value of an item for any AD exponentially (quite literally), and there's absolutely no action anybody can take against it other than one mastery in the defensive tree and ritualistic prayer or volcanic sacrifice. If someone (frail champions especially) is incredibly unlucky (like me, won't lie) and ends up on the wrong side of the crossbow/bow/gun/boomerang that decides to roll three crits (especially on a low chance, akin to 25%) in a row, that's doubled the dps their gold income should allow them to output at that time, and tends to spell fatality for most non-tanks.

Infinity Edge is the paragon of crit, the Excaliber that helps you exkillaber extremely fast (nearly forgot my Kappa). In that, it allows one autoattack to hit harder than any other targeted nuke in the game (assuming both are fully built), and an Autoattack has a cooldown (analogical to AS) of about .75s (assuming 1.5AA/s (assuming the math is right)). Just looking at the item itself

4k for 80ad 25% for that 80ad to become 200ad due to the passive. assuming you only have that, the net dps/aa increase is 110 instead of 80, which is a pretty crazy power spike, even if you have all three components before you combine them. That net dps/aa increases exponentially as more crit is built.

        *theorycraft*

What if Infinity Edge if it couldn't proc its own unique passive. Let's just say goodbye to the inherent crit chance and require you to base your build to spec max crit, with IE not being the first item on that build. That would cause an entirely new line of ADC build. Interesting consequence, will post a thread about what that would do later. end theorycraft because that's not what we came here for

With some help from RNG and a little attack speed, almost any AD can burst harder than the archetype literally called burst mages with no fear of an enemy mitigating said damage because it's all targeted autoattacking. Should RNG allow one role of champion to outclass another, when that "another"'s role is to literally do only what sustained damage ad's do better?

The only thing that I can really see justifying crit in League is that it is a DPS gate for AD champions. It unlocks that fabled DPS for only a select few champions that can utilize it, instead of having Fighters have easy access to high damage through pure numbers (if crit didn't exist here), it gates it behind gold and fraility.

        *I'll be on to edit and expand upon this tomorrow when I'm all refreshed and fun again.
        *Might sound like I'm trying to QQ but I'm 100% curious as to why RNG is allowed to decide the dps of an ADC. Nothing                               anybody can do if either team gets good rolls. Also trying to start discussion on the mechanic itself.