Agreed, but I think maluses allow for more direction to a unique playstyle. For example, let's take Mali, a civ we want to go for a gold-based playstyle and largely ignore production. We could just up the gold yields (via trade, tiles, districts, whatever), but the civ would become way too OP before production became ignored. A malus to production allows you to get the desired effect without giving OP yields to entice the desired playstyle. While you can get some unique civs without maluses, they are still subtle and often ignored. To get the profoundly unique playstyles, like Babylon, I think maluses are necessary. At least, without making everyone OP in their own way or just abandoning any pretence of balance.