Christmas Tree Effect.
There are also tons of other issues in the game that people are always looking to mitigate or ameliorate with errata, FAQs, and houserules.
When you are trying to solve problems, you can't start at the halfway point. You have to go back to the source. So, I ask myself (and you):
How many of the problems in the Pathfinder RPG start with the d20?
Base Attack Bonus, Skills, and Saves are all balanced against the roll of a twenty-sided die. Damage and Skill/Save DC's are built off of expected BAB/Skill/Save Bonuses. Classes are balanced against one another (in part) based on a sliding scale of Full, Three Quarters, or Half BAB; Good and Bad Saves; Class Skills and skill ranks per level. Many things, like traps, poisons, diseases, and natural hazards, but most importantly Spells, Spell-Like Abilities, Supernatural Abilities, and other special abilities, are balanced against anticipated Saves, Save DC's and Attack Bonuses. Everything down the line: Damage, hp, unique powers, in-game loot, CR, Wealth-By-Level, etc., are determined (at least in part) from this foundation.
Gameplay is this weird combination of Embracing and Mitigating, Challenging and Marginalizing, Utilizing and Distrusting, Championing and Forsaking the Twenty-Sided Die.
But, is there a better option? I would never choose to eliminate the element of chance from the game. It would not be worth playing. But, I know there are game systems out there that use d6, 2d6, and d100... and probably others that use other systems I don't know about.
If Pathfinder 2.0 were a reality... and you were building it from the very ground up... would you start with the d20?