As we all know, that line of spells becomes incredibly good with even a little CL advancement, essentially auto killing everything not of that alignment in range, or at least taking it out long enough to allow you to finish the job as your leisure.
So I was thinking about how to make this sort of thing more usable without being horrifically broken, and then I remembered another spell that is semi related. Specifically I'm thinking of Dismissal mechanics.
If the Blasphemy line allowed a save modified by the difference between the user's CL and the target's HD like Dismissal does against whatever effect it would have it wouldn't be an auto kill anymore. Massive disparities still come pretty close to that, which is why this would probably have to be paired with a CL cap on staves similar to what casters normally get. 'You cannot emulate a CL higher than you could actually cast regardless of the check.' would fix the CL 9,001 issue, while still allowing for emulation of the auto scale staff mechanic.
It's still not perfect but is a significant improvement. The main issue left is that something with HD 10 higher (say, any half fiend monster really) is still forcing an AoE save or die with a jacked up save DC. Maybe the HD based lines should be changed to degrees of failure?
Equal to caster level Dazed
Up to caster level -1 Weakened, dazed
Up to caster level -5 Paralyzed, weakened, dazed
Up to caster level -10 Killed, paralyzed, weakened, dazed
Except instead of being based on the targets HD relative to your CL (which would give double resistance basically) it's based on how much you failed the save?
So this hypothetical half fiend whatever with 10 HD on you is forcing you to save at a DC 10 higher than normal, with the effect dependent on how bad you fail the save. So if you fail by 10 or more, you still die. Only issue is this results in an odd mechanic as written where passing the save still renders you dazed 1 round, unless you actually exceed the DC.
This however is easy to fix, and gives us the final version.
The reason why the +1 on the DC is there is because it's easier to remember than passing the save exactly, and still being dazed for one round. The other degrees of failure account for this +1, so it's not actually working any better, just smoother.
Feedback, anyone?