Possible save or die suggestion: since the whole damage thing basically makes them SoD, making them kinda redundant, how bout give them all two saves, like Phantasmal Killer? If you make the first one, nothing or something mildly irritating (for high level) happens, if you make the second but not the first, something mildly irritating or quite nasty (for high level) happens, if you fail both, you die or are otherwise screwed. Wail of the Banshee, for instance, might be 1d4 points of negative energy damage/2 caster levels if you make your first, 1d4 negative levels (and the damage) if you only make your second, and death if you fail both. Have the second save be lower than the first and/or delayed, maybe?