Remathilis
Legend
So why should we stop at where Blue Dragons live? Why should Blue Dragons only have a Lightning breath weapon - that does not seem very realistic - just give them whatever breath weapon you feel like. And why should Blue Dragons even have to look like Dragons? I think Blue Dragons would be even better if they were green coloured and looked like Orcs so that I can have three of them sitting in a 10 by 10 room guarding a pie.
This actually raises a very good point.
We've discussed "lore" in the sense of things like monster stories, ecology, and place in the game world. Yet we somehow give the mechanics of the game a pass as if to say "as long as the numbers are the same, we can do whatever we want with the lore."
Why stop there?
Why limit kobolds to 1 HD? Why not have a version in the MM that is CR 20, legendary actions, and regional effects?
Why should all trolls be susceptible to fire and acid damage? What about a version of trolls that are immune to fire (or regenerate faster from it!)
Why should all fireballs be 8d6? What about printing a version that does 24d6?
Why should all elves be medium size? Why not put a version in the PHB that is Tiny and proficient in cooking utensils, cobbling tools, or toymaking tools?
Why can't there be a version of wizards that can heal, monks that can use greatswords, or barbarians who cast fireball? Why are you limiting my creativity?
Why should D&D lore force me to accept all of these things? I want my tiny-elven barbarian lobbing 24d6 fireballs at CR 20 kobolds and I want it to be rules-legal!