Spells that would normally improve with caster level (i.e. magic missile, scorching ray, create undead) don't.
How about dispel magic? Always 1d20 + 5, greater 1d20 + 11? Would Heighten increase the bonus? In that case Heighten would be sort of required to dispel anything at high levels.
BTW, I find all the monk bashing sort of hilarious when in our current low level game one of the monks is the most powerful combat character.