Voadam
Legend
it removes one of the only penalties built into the prestige class system.
Sigurd
Can you expound on this? Do you mean caster prestige classes that give some but not all levels as +1 spellcasting.
An eldritch knight for example will still be down a minimum -2 caster levels, meaning he will miss out on his top level of spells. Missing the top level of spells IMO is the significant power balance part, not the minor -2 on spell penetration rolls.