Changes in Pokemon Teams
Ash's changed team
Kanto:
* Squirtle-Wartortle: Could've evolved to denote its power in the Squirtle Squad
* Primeape: Ash would have it in reserve like Charizard
* Haunter-Gengar: Sabrina would return Haunter to Ash
Johto:
* Larvitar: Would've stayed with Ash under permission of its mother. Ash would store Larvitar with momma when not part of the team. Would've become Pupitar
* Quilava-Typhlosion: Not only would it evolve earlier, but get over its awkard teenage stage
* Eevee-Espeon: It would be awesome
* Poliwhirl-Poliwrath: Ash's first trade, with Misty
Hoenn:
* Corphish-Crawdaunt: Evolved in the Sinnoh Tournament
Sinnoh:
* The Porygon line: Unlikely, but if they ever managed to shed the stigma it deserves to be a companion
* Hippopotas: Please stop teasing us
* Riolu-Lucario: Cool typing, shows off his friendship and nod to the 8th movie
Unova:
* Ducklett-Swanna: Ducklett would be a recurring antagonist that Ash restrains
* Darmanitan: He had two Grass types, two Water types...I just want the theme to continue
* Female Frillish: Counter to Trip's Frillish, and have it possess Water Absorb. For added humor, it and Trip's Frillish are fond of one another
* Meloetta: She clearly wanted to be with Ash. To prevent Ash from becoming a Mary Sue, have Meloetta only appear in huge battles or emergencies. She's the female Charizard, basically. Not officially owned, mind you
* Zekrom: Briefly tame to counter N's Reshiram, then they go off on their own journey. And I submit to you, Ash riding a Zekrom
Brock's Pokemon
* Geodude: Have it evolve
* Stantler: Should've gotten it
* Ditto: I love the irony of a wannabe ladies man getting a Pokemon known for...breeding
* Vulpix: He should've kept it
Misty's Pokemon
* Togepi-Togetic: Should've evolved much earlier to protect its mom
* Horsea-Seadra: Didn't do much as a Horsea
* Wooper: The thing's adorable
May's Pokemon
* Swablu: STOP TEASING US
* Feebas: This Pokemon was created to show off the contest mechanic
* Phione: Phione isn't that legendary nor rare. Have her befriend one as a nice nod to Manaphy
Max's "Pokemon"
* Ralts and Shuppet: Just because you can't train a Pokemon doesn't mean it couldn't follow you around
Dawn's Pokemon
* Grimer: I don't see why not
* Ambipom: She keeps it
* Buneary-Lopunny: It evolves through happiness
* Rotom: Instead of Togekiss. Rotom's quirky behavior seems like a fun Pokemon to be part of the team
Iris' Pokemon
* Axew-Fraxure: It wanted to evolve
* Deino: For someone else to be in her hair. It's adorable, a Dragon type and they teased it
* An Ice type: To help her get over her fear of Ice types. For bonus points it should be a scary-looking Ice type
Cilan's Pokemon
* Vanillite: An ice cream Pokemon? With a Pokemon conisseur and cook? Win
Team Rocket's Pokemon
* Ferrothorn or Maractus: James' Pokemon have a long history of being Grass types that hurt him
* Weepingbell, Arbok, Weezing: Jessie and James should've kept them
* Tynamo-Eelektrik: Jessie usually gets serpent Pokemon, and this line is the closest to that besides Snivy
* Golett: A habit of mechas
* Any Ground type: They think it'll make them undefeatable against Pikachu. Well...
Tobias
* An actual backstory and foreshadowing. Tobias would show up now and again, hunting for rare Pokemon
* A shiny: He's a rare Pokemon hunter
* Primeape: How else would he have obtained a Darkrai? It can't be put to sleep and has a type advantage
* Cresselia: Instead of Latios
* Unova Pokemon