Actually, I think both are unclear. Spell that cause multiple save usually make it more clear that such is the case, I'm inclined to believe that someone attacking someone else who has stunning barrier is only required to save once. Though it's not impossible to work per swing, since the basic version ends once it stuns someone.
However, the greater version working per person makes more since (can't stun the same person multiple times) and it doesn't matter that you probably wont have enough opponents to use up all the stuns, it just means the spell ends when its duration runs out.
I do feel your point about saving once per round makes sense. However, I suppose that's the problem here. If the the spell only works on each creature once, it should be specified in the description, isn't it?Actually, I think both are unclear. Spell that cause multiple save usually make it more clear that such is the case, I'm inclined to believe that someone attacking someone else who has stunning barrier is only required to save once. Though it's not impossible to work per swing, since the basic version ends once it stuns someone.
However, the greater version working per person makes more since (can't stun the same person multiple times) and it doesn't matter that you probably wont have enough opponents to use up all the stuns, it just means the spell ends when its duration runs out.
It should, but the spell doesn't make sense when it talks about stunning a number of creatures if it can stun the same creature multiple times.
Either the spell should only be able to stun a total number of times, but could work multiple times against the same creature or it can stun a total number of creatures but only once per creature.
Otherwise the spell can stun a single creature ad infinitum (until the duration runs out) but likely would never hit the creature limit, which seems unlikely the desired design.
If we changed it to say the spell is discharged after stunning creatures a number of times equal to caster level it makes sense. If we say it can stun a creature once, but stun a total number of creatures equal to caster level that seems fine.
But if it can stun the same creature multiple times, and doesn't run out until you've hit the total creature number cap that's where things are inconsistent and don't make sense.
It honestly looks to be just a simple case of poor word choice... it's pretty clear that the intention is for it to have a number of charges equal to your caster level that get expended each time it successfully stuns a target...
It honestly looks to be just a simple case of poor word choice... it's pretty clear that the intention is for it to have a number of charges equal to your caster level that get expended each time it successfully stuns a target...
I agree that would be a sensible way to run it.
Keep in mind, if I am full attacking someone with GSB on, and on the first attack, I fail my save, and since I am now stunned, all of my remaining attacks are invalid and don't resolve. With this in mind, there is no "being stunned multiple times per round" and rolling once per attack makes sense.
[Edit: You actually don't need the greater version for this to be the case, but the spell won't simply end with you unprotected from the second person who walks up and attacks you after the first guy is stunned.]
I don't think anyone was concerned about being stunned multiple times per round, that is clearly impossible since once you're stunned you can't attack the rest of the round.
What the concern was is that if every attack you make in a round has to make a save, then the chances that you fail go up quite dramatically.
Lets think about a high level character that has 5 attacks from whatever methods will get them there vs a heightened version of this spell (normally the save wouldn't be too high because it's a 3rd level spell but heighten is an option).
Let's assume that the person attacking has a 20% chance of failure, that's not too bad. But if you make 5 attacks against the creature your chance of failing is 1-0.8^5 = 32.8% You went from a 80% chance of success per attack, but only a 33% chance to make it through the round without being stunned. That's awful.
And that's why I think it should be limited to once per round.
The way you said "if it can stun the same creature multiple times." made me think you thought you could keep attacking even if you fail, not "has a chance to stun multiple times".
I mean, maybe, but if you are heightening the spell significantly to where the save is a threat, then you're burning a high level spell slot to do so and I would say that it's working as intended for a powerful spell to only stun 1 round. If you are doing something like heightening it to a lvl 9 spell for free with spell perfection, even then I would say that's as intended as you also had to get 4 feats to do this. Even as a DC 18 save, that's better than for example the enemy casting fly and just not being hittable at all by the melee guy. You can also choose to not keep attacking on your full attack when you get to your lower bab attacks that aren't as guaranteed to hit on the scrawny wizard so you aren't losing reward for your risk.