When I ran my Primeval Thule campaign, I strongly wanted to ramp down the magic level of the game. I went pretty medieval on the rules after a bit of back and forth. Basically, no classes with cantrips. They might be NPC's, but, the players cannot play any classes with cantrips, full stop.
It did lower the magic level considerably, although, the players still wanted their magic toys, so, I wound up with a monk, a paladin, a ranger and another ranger out of 5 PC's. :'(
Still had TONS of magic in the game.