Hot take: MewMew doesn't deserve to get nerfed

It's chapter 5 secret boss. Those are supposed to be difficult. By this point people are likely to be hoarding more food in their inventory than Asgore's fridge ever saw. I think it's perfectly ok for a chapter 5(!) secret boss to actually be enough of a challenge to make you dig into your item supplies, especially considering how strong rewards you receive after it.