Dungeons and Dragons 3.5 was absolute nonsense balance-wise, but it was remarkable because it was imbalanced in a whole variety of different ways that are good object lessons for designers to take on board when making your own RPG content. So, rather than one huge master-post explaining it, here’s one example:
You’ll find if you listen to any given D&D 3.5 player, they’ll usually have some memories of the things I talk about being total bupkis. I know I played alongside a cleric who wasn’t overpowered, and we had one game where the runaway behemoth was a telepath. As your friendly neighborhood min-maxer I had the game squealing under the heel of a bard, once. More often than anything else we’d see on the newsgroups players wondering about how they could play clerics well, because they thought their only job was standing by and healing, leading to an unfulfilling game of whack-a-mole. What’s more there are a lot of games where the wizard player felt worthless and ran away from goblins a lot with a terrible armour class. Once I heard the artificer dismissed as trash because a player could simply not imagine how to make it work.
This is one of the many ways D&D3.5 was unbalanced: It was entirely possible to play overpowered characters badly. Most of the characters who were busted were busted because of spells or magic items and that stuff was overwhelmingly available…
If you took it.
You could absolutely play a weak wizard! You could pick up the twenty totally worthless spells at every level, you could sink into the swamp of crap. You could take a level of sorcerer and a level of wizard, and then maybe level them up side by side and maybe you’d balance your stats and oh good god noooo.
You could be handed a high-octane chainsaw laser hammer and it was entirely reasonable for a new player, a player who had no reason to expect they were being given something totally broken, to sit down and tap nails in with the wrong end.