Gen3 was my least favourite in Pokemon. There I said it. I always found the Pokemon in Hoenn very uninteresting and it was a massive disappointment after playing Gen2 which was like the greatest thing to ever happen. Gen1 always has nostalgia value but Gen2 was just perfect in so many ways. I also loved Gen4 and didn't like Gen5 :P
I hated gen 2,i despised even more gen 4.
I got used to the inconvenience of gen 3,but God it's does suck.
Basically gen 2 had fucked up leveling because they tried to do a hyrule field/sandbox bullshit and they failed hard, then we have a whole new region! With only 3 side quests, even more stupid level gaps making it barren as fuck...yet people still praise it somehow, the only decent stuff there was Red snorlax, seriously that was the only half challenge gen2 had. Then you get 2 new types! Wich you will only get to use in the game either in the post game or if you evolved eeevee at night, or used pineco for wathever unholy reason as it is the only option in gold since silver also has skarmory.
Gen 3 is inconvenient in every sense, at least it introduced the battle Frontier and synchronize+everstone.
Gen 4 gave us great stuff with competitive and breeding stuff, even wifi. But God... Mt coronet blocking everything, marshes, snow and the worst HM blocking syndrome of all the games... Jesus at least we got a breeding route, and the battle zone for actual post-game.
Gen5 did everything right, some sandbox lovers might hate it for being too linear or having very few extra zones to its routes, but dex wise it was the absolutely best both for ingame and difficulty design, most of the dex was made of clones of previous roles, but God they actually made them work in their level context and even gave us the brilliant introduction of non stone evolving early ice types with rare game breakers such as maractus for those that actually explored. And then there is the world tournament, the biggest fanservice moment in the franchise. There is also LO hydreigon from Ghetsis, eat your heart out Cynthia and Red, this Is a real fight without the need of level jumps.
Gen6 is decent dex wise but it kind of falls flat with uneventful fights in every sense yet it breath a lot of new air to competitive with Megas.
Seriously I'm a gen 5 and gen6 F.A.G. and I have been playing since blue, but seriously I still can't see how people praise jotho or say it has a post-game due to having a new region with virtually nothing, gen 4 wich I despise with a passion pulled this better with the battle zone in every way and until b/w b2 /w2 blew it out of the water DPPT where the definition of post-game in the franchise.