Your insight and/or opinions, please.
The DM decrees that PCs (and NPCs, out of fairness) are prohibited from taking two consecutive levels of the same spell-casting class as they gain experience -- if you want to progress in that class, you've got to multiclass with something else inbetween levels.
At the upper bounds, this has the effect of limiting 20th level characters to 10 levels of spells -- or two sets of 10, if alternating between two magic classes.
The goal is a campaign wherein truly powerful magic is harder to come by.
What other effects could be expected or should be considered?
The DM decrees that PCs (and NPCs, out of fairness) are prohibited from taking two consecutive levels of the same spell-casting class as they gain experience -- if you want to progress in that class, you've got to multiclass with something else inbetween levels.
At the upper bounds, this has the effect of limiting 20th level characters to 10 levels of spells -- or two sets of 10, if alternating between two magic classes.
The goal is a campaign wherein truly powerful magic is harder to come by.
What other effects could be expected or should be considered?