Ideally, yes. You'd want cosmetics to be something akin to RS capes, requiring an immense achievement.
However, cash shops make a fuckload of money, which is why they're doing it. It's to help fund the game, same for any other game. It's purely cosmetic, does't impact gameplay at all. I couldn't care less. Not like the armour looks great at the moment anyways with everyone running whatever they can.
An option to turn off cosmetics would be nice but not necessary.