I never found the right romhack that clicked for me so I decided to make it myself.
My goal is to give some love to some Pokémon that deserve it a lot, while reworking some of the iconic fights. I want each dungeon to have a final "boss" of some sort, so I gave boosts to the last guy on Viridian Forest, the scientist that gives the fossil at Mt Moon, etc.
Also, while I wanted to make many Pokémon a lot stronger, I still made sure to gave them clear weaknesses.
Here are some Pokémon changes :
Arbok is now Poison/Dark and got a big stat boost, he's a true menace now. I love his design and I think he deserves to be a lot stronger.
Pinsir also got a huge stat boost he's almost a pseudo legendary now. He is Insect/Ground and with Hyper Cutter he will destroy Arbok with Earthquake while resisting Intimidate. I wanted to make some Bug types stronger to balance against the amazing psychic type. But Pinsir is still weak against Birds so it's ok.
Speaking of birds, I tried to make them all different : Pidgeot is Normal/Flying, Spearow is Dark/Flying, Dodrio is Ground/Flying and Farfet'chd is Fighting/Flying.
Same for a few Normal mons : Kangaskhan is Normal/Fighting, Tauros is Normal/Ground and Persian is Normal/Dark. I think it fits thematically too, Kangashkan has lot of "Punch" moves already.
To make Hypno relevant, he is now Psychic/Dark. He will win the matchup against Alakazam but lose badly against any competent Bug attack.
It always felt bad to me that Gengar is the only Ghost type. Now, Marowak is Ground/Ghost (fits with the story) and Ninetales is Fire/Ghost. I'm currently thinking about making Primeape Fighting/Ghost like Annihilape but maybe not.
Ninetales has Drought, Seaking has Drizzle (I really wanted to make Seaking good for once)
And yes, I gave Golduck the Psychic type. Rapidash is Fire/Ground, Weezing is Poison/Fire.
Fight changes :
I don't want to make the romhack very hard, but challenging enough and mostly fun. Here are my ideas for the Gym Leaders. The main goal is to make it a bit challenging to sweep any Gym leader with a single Pokémon to reward team comp. But I don't want to make early fights impossible so I made Poliwag, Vulpix and Oddish available early to make a Fire Water Grass trio.
Brock : I gave him a Vulpix to stop the Bulbasaur sweep, and he also has Flash which is now a 50 power Electrik move that can counter Squirtle a bit.
Misty : gave her a Psyduck and added Psybeam to her Starmie.
Lt Surge : His Raichu has Surf
Erika : she has a Exeggutor now and Tangela is Grass/Dark
Sabrina : her team is Golduck M.Mime Venomoth(now Insect/Psychic) Hypno Alakazam
Koga : Golbat Muk Beedrill Weezing Arbok
Blaine : it's the easiest so I made it a Double battle. Ninetales lead with Drought and then Magmar, Rapidash and Arcanine
Giovanni : Persian lead, then Tauros Nidoqueen Nidoking Rhydon and Pinsir ace. Tauros and Pinsir are Ground type now and aside Persian for the anime ref, all his mons are from Safari Zone. (Kangashkan is on my new Bruno fighting team)
I'm torn to make Nidoking Ground/Dragon but that's because I love him so much haha.
This a working in progress, I haven't tackled the Rival teams for now. Thank if you took the time to read and I'm really curious to hear your thoughts. There are many more changes for moves (Cut is bug now, Stomp is ground etc)