Voadam
Legend
It is a fairly elegant way to cut the PC caster power, it just means you lose out on the upper level spells as players entirely and the casters go from quadratically strong to fairly underpowered for their level except for some specific builds. Dipping into a caster class can get you the use of wands for instance at the cost of 1 BAB or a level back on the sneak attack accumulation. It also calls for adjudictions of whether bards and spellcasting paladins or rangers count as spellcasters.Andy Collins had discussed a campaign of his own on his website in which characters could not take back to back levels in a spellcasting class (I don't recall if it was the same caster class or any caster class).