>>583574671a. Countering Iron Defense is way easier than Evasion. Iron Defense will only reduce damage from physical moves, not special moves. So you already have half of all attacking moves you can use to counter Iron Defense easily.
In contrast, Evasion only has so many moves that can bypass accuracy and they are either exclusive or weak as shit.
1b. Additionally status moves are 100% unaffected by defense buffs like from Iron Defense. You can always use Taunt, Trick, non-poison Toxic, Will-o-wisp, Spore, etc. so you also have all your status moves as options as well.
2. No matter how high your Def or SpD get, you will always take damage from an attack that you’re not immune to. If the opponent is at 1 HP, they will never survive an attack with 100% accuracy.
3. Because its entirely luck based, matches can easily be swung through dice roles rather than skill, which is the core issue with Evasion.
Even if +1 evasion is just missing 25% of the time, that doesn’t mean you can’t miss 4 times in a row. Sometimes you never miss your attacks. It’s all dice rolls and players should be encouraged to play skillfully instead of relying on rng to win.
4. As a bonus, Evasion is just heavily stacked compared to Accuracy, which is just stupid.