I read this excellent article over at The Blue Bard while I had a free moment today:
Say Yes to the Players
It is full of excellent GMing advice, most of which I'd summarize as "let the players do cool stuff with their cool powers, and have it lead to more adventure" plus "don't nerf them to maintain a feeling of control."
How generous am I with "Yes?" I'd say not very.
Some of it is my personality. Maybe a lot of it, is. I'm a "let's try it and see!" person in real life, but I tend to build somewhat restrictive game rules. I find, personally, that constraints force creativity in a way that blank slate of freedom often does not.
Also, I tend to look out for ways something can be abused. I may put the tool into your hands anyway and tell you, hey, it's abusive, don't blame me if you allow it to be so abused . . . but if possible I make things work in a way that give you X without leaving a gap for Y and Z.
I will put in rules-based "nerfs" on things I feel like are too powerful for the game we're shooting for, although I try to make the "nerfed" version feel better for the game in the process - Turning, for example, chasing off the weak undead but weakening the strong instead of just flee or fine.
But I will also clean up rules full of issues or just weakness and make them more powerful, if that makes sense - Animate Shadow, say, or why I allow multi-turn free energy on missile spell buildups and combinining spells that the system keeps separate (Flesh to Stone/Stone to Flesh, or Missile/Explosive Missile spells.)
In play, though, I'm usually going to make a restrictive but not an expansive ruling. As we play AD&D, I'm trying to be more expansive there. Everything there is much less easily replaceable. In GURPS, everything is too easy to get.
Let's take an example of "give them power with yes" versus "nerf things" - Wishes.
Wishes: I know what, or what kind of, power grants Wishes in my games, so I don't use the 60/40 roll mentioned here. I make them quite powerful and quite broad. Still, players will try to simultaneously expand them and constrain them with a carefully-worded wish. It's worked about as well as you would expect, even given an actual lawyer, an author, and a rules-and-fine-print-expert manager in the group. In other words, not well. The ones they made that were broad but clear worked fine. In general, though, I prefer to make wishes powerful.
I can do so because they're rare. If it was a common, spam-able spell, no.
The example of Stone Tell in the article is a good one - the players used it in a perfect circumstance. It's a 6th level cleric spell. It should be pretty effective - and it can be. Change it to Seek Earth - a cheap, easy, high-percentage success rate spell that you can cast over, and over, and over, and over again . . . and I'm more inclined to a restrictive, not expansive, reading of it. Why? Because it's effectively unlimited. Finding ways to keep challenging that - the Find Traps example - is a good one . . . but it's possible given my game system of choice that it's not really "challenge that spell" as it is "the game has changed fundamentally from this yes."
When a player comes up with a clever use for a one-shot potion that can't be purchased in town and is rarely found, that causes some outstanding and exceptional effect, I'm for it. When the same player comes up with a clever use for a one-shot potion easily purchased in town, readily found, and routinely used already in my game, that causes some kind of outstanding and exceptional effect, I tend to put restrictions on it. Again, it's effectively unlimited. Once a player finds some way of turning a Potion of Healing into free unlimited healing in some way or finds a way to make it heal or kill, depending on how it is used . . . the game has fundamentally changed. Not just for "high level" play, but for all play. GURPS Dungeon Fantasy doesn't restrict much by "level." You're restricted by points and cash, and in a game played around finding cash and earning points, that's more of a speedbump than a true restriction.
Some spells and powers just make some problems go away - Create Servant is a game changer that I allow. So is Levitation (and one I made cheaper, easier, and better for the most part). So is Seek Earth. I am fine with that. I'm just going to be much more careful than I would in a limited-use game system, And ultimately, I think that's okay. Your GMing has to match the baseline reality your rules put forth.