What if Crits weren't RNG?
Crit builds will never have a satisfying laning phase because until you get three or more fully-built crit items, your damage output becomes highly dependent on RNG. You might randomly get the damage you need to win a trade or get a kill, and that doesn't feel good for anybody involved.
Imagine if instead, crits were reliable. Every third hit (without leaving combat) would be a crit, and base critical multiplier would be a stat inherent to individual champions. Crit items would boost that critical multiplier (like IE's unique passive), and finished items would create additional crit conditions (e.g., automatic crits on immobilized targets, crits every other auto if you are above 75% HP)
This would do a variety of good things. First, it would remove RNG from marksman damage. Their damage output would be predictable and reliable at every stage of the game. Second, it would make marksman damage less frontloaded. They would need to commit longer to trades in order to get that crit off, increasing interaction in lane and giving both players the opportunity to play around each other's crits. Finally, it would add an additional tuning knob for individual champions. Since each champion would have their own base critical multiplier, the devs would be able to change that to affect the champion's damage output.
Randomness has no place in League.