Something that I’ve been seeing a lot in older games, that appears to be less present in more modern games are the side-effects of casting spells. Premature aging, madness, spells trapping people in stone, and so on. While I don’t really lament the evolution of gaming like OSR purists, I do think that magic without consequences is less interesting.
Add this to the list of things described as, “if I made my own game…” because really this is something that needs to be a part of gaming. And honestly, this is really something that should be core to fantasy gaming. Then again, having side-effects for magic really reflects where the game has inferences about setting. The assumption that wizards are somewhat unstable and taking outrageous risks to impact the very fabric of reality is a palpable part of the game design.
I feel like Pathfinder and D&D 3.X are kind of where game design shifted pretty significantly, and not in a bad way. However, there were changes that were made, like side-effects for magic, that really should not have been cast away. Rules like this go a long way to wards influencing gameplay, and I would love to see this kind of stuff make a regular return to fantasy gaming.