I literaly made the system we run on, and many things regarding the game mechanics, lore or various decisions happen between smurf and me via PM.
you want a nerf?
Paper Dragon, big category spell (cost: 6 mana) deals d(mag*2.5) damage, alternatively if it gets patched, deals d(mag) + (80% of mag) damage.
this is literaly how the rules of the game work, and the only way to make sure it is REALLY balanced with regard to other players, who play with the same rules. I do not understand why Sen needs to roll dice that are chosen at random, that are in no way tied at all to the system of the game. 100d8? 15d4? How is that correlated to anything? One can not balance an attack to a system if you refuse to correlate them to the system. If you insist on making paperstock a secondary resource besides mana to further empower attacks, note that you are getting this power for free, on top of your already existing power - so it's literaly a bonus of power that nobody else has - which is hardly fair towards other players. Sure, it runs out, but at the start of the battle, you are stronger than everyone else at no downside
as such, there needs to be a downside to having no paper left besides *Sen is now suddenly not stronger than everyone else anymore*.
I propose this:
1% of paperstock can be used to empower a paper based attack, to raise the damage done by 1% (or even 0.5%. Or possibly 1.5% or 2%. As Rolep has shown talent on this, I'd like it if he ran some numbers on that. This can not be decided without any numbers). When paper has been used to empower a paper based attack, it is lost, paper that is just used on a standard attack can be reclaimed. The downside is, when paper stock is at 75%/50%/25%/0%, the base damage on paper based attacks is reduced - by half that amount. Run out entirely, and you can not attack with paper anymore(duh)- now you are limited to the (huge) arsenal of Sens non-paper basede magic - which does halved damage compared to the normal scaling of magic.
This means Sen will actually have to think about when it is the right time to boost her spells. She can still fight normaly at no downside, at the same strength as everyone else, or choose to boost her damage output by not insignificant amounts (again, needs some statistics here) for a few attacks, but at the downside of weakening herself for oncoming combat, should the battle drag on. This way, the extra paperstock is a tactical resource, that needs to be used with care, rather than just a straight on power-up. Note, this STILL means that Sen is stronger than everyone else - who literaly only perform at 100%.