Note: This article is addressing a fairly standardly designed RPG. There are possible design spaces where some of these will not be true.
Many people, when designing a game, look at enemy stats and PC stats and skills, and then they think of them the same way.
This is a mistake.
The purpose of each is completely different. A PC is running an endurance race. They have to fight multiple battles, with the enemies fighting one battle each, waging a war of attrition on the PCs resources.
This alone makes a huge difference. Skills that would be overpowered in the hands of the PCs, would be fine for monsters, and skills that would be fine for monsters might be overpowered for PCs.
A skill that costs 0MP and TP but attacks two random targets? With a monster that 0MP will not be a big deal. Monsters, unless you build them with really low MP, generally don’t last long enough to run out. But that same skill on a player character would double their damage capabilities for no cost.
A skill that drains all your MP to do a massive attack on all enemies based on the percent you had left? That is a powerful, but fair, attack for a player to have, as it requires a large expenditure of resources. On the other hand, a monster with that ability… well monsters are only around for one combat each anyway, so the resource expenditure means nothing to them.
Also, enemies come in different numbers. If you have 4 PCs fighting a single boss, then that boss needs more ability to do absorb and take damage, otherwise, he will go down super quick. Or if your PCs fight a group of 8 enemies, and each has the damage output of one of your characters, then it can easily be a TPK.
Always keep in mind the context that mechanics fit into a game. Symmetry sounds like a good idea sometimes, but usually, the context is NOT symmetrical.
Can you think of more situations where symmetrical PC/Enemy design would not be a good idea? Can you think of an overall design that would make it work? Tell us in the comments below!