Honestly, I like what
@Calzaghe has thought up more than what we got. Jaune's Arc (I didn't mean for this to be a pun and I fucking hate myself right now) naturally leads him towards a self-sacrificial end especially to save the women he loves and naturally make Pyrrha far more interesting in the aftermath as she has to deal with being largely responsible for his death. Pyrrha in general is also just a far more interesting character than self-insert Jaune, so its an automatic +1 writing points there.
Pyrrha's death is a genuinely good bit of writing, but it unfortunately only good by itself and leaves very little for other characters to build off of in the aftermath besides Jaune whose arc didn't really need it. Ruby would be absolutely livid over losing her first actual friend at Beacon and give JNPR the kick in the ass they need to start taking shit seriously.
I get that this is all just fanfiction and would require actual competent writers to accomplish it. But it creates a far easier writing environment and gives loads more content for the characters. Good writing typically creates a plot that will make things easier on the writer rather than harder, and killing Jaune instead of Pyrrha does exactly that.
Ironically, killing Jaune off at the fall of beacon would actually reward all the time his character stole from everyone else rather than serve as a further critique of this series god awful writing.
There is one potential problem to all of this.
Jaune plays to the old "underdog audience surrogate" formula, and starts off weak, which means that on paper, he's got plenty of room to grow and develop. Even if he's not malding at Cinder or angsting at Pyrrha's death, you could insert him in any different scenario and he'd still be easier to write on paper. Just ask Coeur Al'Aran - his fanfiction page is literally full of this.
Pyrrha's room for growth is limited unless the writers are smart enough to introduce new arch-nemeses and scenarios to keep Pyrrha more multifaceted than just going on a Cinder vendetta 24/7. Maybe being heartbroken that learning her fairy tale role model Salem was the enemy she must fight is one thing, but honest to God, there needs to be stronger opponents to deal with the power creep that Pyrrha's skill set brings to the table, especially if they have a counter to her magnetism.
Second, Pyrrha is fucking OP, even without a portion of the Maiden powers. Athleticism, Magnetism, a versatile set of weapons, OP martial arts skills - and this leads to the same problem for the animators and writers regarding her power levels and skill set - where in order to give a challenge during combat, they make her stupid or use a random BS the same way they did with the RWBY girls to hold her back to create "stakes" and "tension".
Ironwood, Tyrian and Watts can be brought down because of the metal weapons they use, which kinda steamrolls the oppostion.
Remember Weiss being a "spellcaster" because her Semblance was that versatile and her fighting style more complex to animate? Remember Ruby twirling her weapon like a dipshit and standing around like an idiot? Remember Yang going down in one hit getting whacked with an umbrella in Volume 8?
On paper, fanfictions that explore the "Pyrrha survived" aspect (e.g. Vindicta) might work, but I doubt very strongly that the writers are smart enough to let that happen, especially when they're cramming in that Rapunzel story into the show's canon, and increasing the focus on ending the Salem story ASAP with the pacing.
