If nothing else, there are games where what happens in the world can affect player mechanics and games where they cannot. Two different types of games though further differentiated by other considerations too.
And yet I'm on the "the world can affect player mechanics" side. Emphatically so. Like I have said I am an advocate for changing subclasses - and if that isn't impacting player mechanics I don't know what is.
What I'm not an advocate for is
crippling the player character. Change isn't the same as crippling. That which doesn't kill you makes you stranger.
Exactly. We want some in game effects to impact player mechanics. We are also the same group of people who thought level drain, ability score drain, magical aging, etc.. were good fun aspects of gameplay. All of those to varying degrees affect mechanics. We want things happening in the world to have a lasting impact on the PC sometimes.
And the problem with just about all these is that they are
boring. The problem is that literally all the consequences you have named there fit into one of two categories:
- Taking away someone's toys and crippling them until they get them back (removal of spells, level drain, ability score drain)
- Changing around numbers (magical ageing, ability score drain)
It's not the fact that they have an impact that's the problem. It's that they are all crippling and strictly negative.
What I like are consequences. I recently gave someone a homebrew
Hand of Vecna and the way it worked was through a corruption mechanic; whenever they used one of the major powers they marked off a Mark of Corruption. And each time they used a major power they had to fill in a circle - fill them all and they become an NPC. Just a Taste and Megalomania went fast. How fast he got corrupted was up to him.
Marks of Corruption
O Just a taste: The first time you reduce a foe to 0hp after a long rest they return as a zombie under your control
OOO A touch of death: At the first level you look as if you haven’t slept for a week. At the second you look gaunt and haggard, and at the third like a lich
O Blight: Small plants die and larger ones wither in your presence
O Megalomania: Gain a tendency to speechify. You have everything under control. So you think.
Far
far more interesting than "You just took level drain. You lose your best toys and take -1 to rolls". I'm on the "we want this removing things trash out of the way because it's clogging up where interesting things could be as well as making things less fun". And you know what this does? It makes the PCs far more likely to risk the consequences because they know they will be interesting. And their character will get stranger, not just crippled.