One of my players has just come up with a proposed houserule for might strippers. I've introduced my own houserule that might strippers affect might pool, not might score. My player suggested that they instead affect the score but do not stack, that essentially a might stripper applies a penalty to the BASE might.
This, as far as I can see, removes my two problems with might strippers
Low powered might strippers when multicast, or cast by multiple casters can take down very powerful creatures quickly
Might strippers in items can be handed out to grogs, allowing a half dozen grogs with charged item wands to kill dragons.
In this proposed houserule, a level 10 might stripper might well still penetrate the targets defences, but its only going to apply a -10 penalty to the might score. A second level 10 might stripper would apply a -10 penalty to the same original base score, which wouldn't drop the new might at all.
If you want to totally strip a creatures might, you'll need a much bigger might stripper, which of course will be harder to get through the targets magic resistance.
Now, problems I can see.
My saga is non standard and only has the magic realm, so one might stripper would work on anything with might. Therefore a mastered might stripper would be very handy.
It still drops magic resistance, I don't like this much.
Am I missing any other glaring issues with doing it this way?
Make magic resistance depend on Might (what you are not affecting) not Might Pool. Removes your first problem. An empty might pool means a less effective dragon (no breath, no transformation to human, no mind control or animal, no prophecies,...), but he can still shred you into oblivion, or gulp you down. Been there, done that, we liked it
What we added is that a CrVi spell or a PeVi spell can be used as a damage spell against supernatural creatures. That affects them normally, like a damage spell from another source. Use the non-boosted damage progression (read: Ignem-5 and PeCo/An progression) for these damage totals, so a CrVi20 would do +10 damage to a supernatural creature if it penetrates. you still need to overcome soak et al. This was not widely playtested before the normal hermetics saga (we are now playing hedgies) ended, though.
Remove multicasting as a specialization option. If you want to affect more targets, use Group or area of effect spells. if you want to take down a target faster, use a more powerful spell. Easy. Multicasting is one of the (quite a few, granted) things that is so wrong about the setting as to break it IMO, so its removal is not a problem.
It does give a reason for some of the higher level might stripping spells. Start with a level 10 which can penetrate and move on to a 15, and then a 20, perhaps?
I'm not sure how this removes the problem with grogs having items that strip might. It is slightly mitigated, sure. Certainly a magus could create charged items with sufficient penetration with the high level strippers or rather they might take the time to make fully invested devices, since you can take more time to get higher levels of penetration.
The items in the hands of grogs issue was that a magus could, in a single season, make a half dozen wands of might stripping as charged items and under raw, his grogs could use these to kill powerful creatures very quickly by all casting using the wands on the same round.
Of course this proposed house rule means that in the above example, the first item would inflict the penalty but the others would have no further penalty.
And then they bring out the next level might stripping wand. And after that the next level, and so on. They can still make multiple wands, maybe it takes a bit longer, but the grog could be equipped with several wands that do ever more levels of damage as the creature weakens.
I've said it elsewhere, and it bears repeating here. I don't see a problem with might stripping. I think this is especially true under your paradigm where everything is magic might, it's therefore valuable vis. Of course I don't want to strip the might of that creature (too much), I want to kill it and render it's carcass for vis. It might be that I need to strip a bit of might from it so that my sodalis' Pilum of Fire penetrates, but that's the price of doing business. I certainly don't want to take all the might away...
Yes, but traditionally, might strippers lower the might of the creature. So, if I strip 10 might from a might 30 creature, it now has 20 might. With respect to resistance it now has a 20 MR, and maybe other spells with that amount of penetration can now penetrate it. I believe Gribble's HR creates a might pool, which the stripper reduces, but the might is always constant, and so a 30 Magic Might creature always has 30 MR.
I think the proposed house rule is reasonable. As noted above it still allows stacking with a series of higher-level variant spells, but that's quite a hassle to arrange.
I still prefer your original house rule, however. Why is it your players want might strippers? If it is to lower MR, consider allowing simply that with a new guideline, as a different guideline from reducing Might Points. (This may require a duration, rather than being instant destruction.)
The other thing that is so powerful being Hermetic magic itself
But yes, certainly, abolish this abomination.
An alternative I like is allowing the magus to increase the target (to Group, or x10 volume etc). You then effectively trade a season inventing a variant spell for a season (?) learning the mastery ability.