I have a fanfiction alternative story for TLOU2 that I need to get out of my system so I'm cringeposting it here.
Ellie is overcome with guilt for not having developed a vaccine and tells Joel she is going to find new people to develop a vaccine and right what she believes is a wrong. The plot involves rebuilding a medical team, and finding another immunized child sacrifice. They discover that only female children have a chance of being born immune.
While meeting with a group of slavers who claim to have an immune child, they are ambushed and Joel is injured, but not killed. The slavers are killed and the child is rescued, though the lead is a bust because it's a boy. He helps Ellie get Joel back to their homestead and they begin to trust and appreciate one another along the way.
Ellie and the boy go off on their own to pursue another lead on another immunized children, which is a very arduous and troubled trip, made worse by having to leave Joel behind. Ellie naturally assumes guardianship in the same way Joel did over Ellie. During a serious, late-game encounter, the boy is attacked and his gas mask is broken. She fears she has lost him but to her surprise he is in fact immune - and born a girl.
The group of survivors they were chasing after are all dead and they return home. Ellie wants to keep his secret, but he decides - on his own - he wants to announce it, and does so. Despite being explicitly informed on the fatality of the vaccine research, he accepts his own death for the greater good. Ellie is gutted but respects the choice. The vaccine is developed, and efforts begin to distribute it.
The game ends on promises of hope but also trouble. The next sequel is set up as it's hinted selfish groups seek to use the vaccine as a mechanism of control and power.
---
My story:
1. Respects the original franchise by not killing major characters just to establish the new ones like every shitty fucking sequel ever has done.
2. Keeps the game focused on the original cast while expanding it naturally.
3. Gives characters clear, logical ambitions that they endeavor to achieve on their own instead of being forced into it by circumstance.
4. Integrates contemporary moralism (which I assume is mandatory for any major release these days) logically with the story, instead of shoving it in your face and expecting you to care.
5. The pains that Ellie suffer are the same as what Joel would have experienced with losing Ellie. That she pursued this on her own and allowed it to happen is a character arc and personal development. It's like poetry, it rhymes.