First of all, I hope you're as excited for this event and the upcoming new anime season as I am.
Yowamushi Pedal was my first sports anime/sports anime fandom, so it's always had a special place in my heart. Hopefully this letter gives you a better idea of some of the things I like, but really, so long as you avoid my few strong Do Not Wants, I'll be excited for any new Pedal content.
This is just a placeholder for now so I have something to link to, but I'll have a real letter up here by the end of Thanksgiving weekend.
My favorite characters are Kinjou, Arakita, and Koga. My favorite pairings are Arakita/Kinjou, Kinjou/Makishima, Manami/Toudou, T2, and Kinjou/Koga.
To get it out of the way, the main things I Do Not Want are major character death, unhappy endings, or non-con. For relationships, please no Makishima/Toudou or T2 with anyone other than each other (though a T2 OT3 would be cool if you wanted to go that route).
I love both fluff and angst. For the fluff route, I love domesticity and team bonding. Some possible gen ideas would be Sohoku going on a team trip to Akihabara with Onoda, or the team gathering at Makishima's to watch Tour de France footage. If you want to go the shippy route, I have a huge weakness for characters cooking together and for hair washing/combing/braiding and gentle touch/hugging/cuddling. I also like, shippy or gen, thinking about the third years when they go off to college, especially Kinjou and Arakita at Yonan and Shinkai and Fukutomi at Meisou.
If you'd rather go with angst, one thing I love seeing explored in sports anime is how different characters deal with injuries. Some ideas for that would be how Kinjou and the other Sohoku third-years deal with Kinjou's injuries at the previous Interhigh, or how Arakita deals with an injury in college given his history with the baseball team. My pet headcanon is that Koga and Kinjou's relationship grew out of them both being injured in the Interhigh and their recovery from that, so I'd love if someone wanted to explore that further.
If you want to go the NSFW route, I'm not a huge fan of PWP. I'd much rather see NSFW content used as a way to explore the dynamic between two characters and the trust in their relationship. My tastes in NSFW tend towards kink, so some ideas there would be piercings/bondage/sensation play.