We aren't being hard enough on this generation.
DP are unplayably slow. I’m serious, I can’t replay DP because of the speed and the absolutely atrocious variety in the regional dex (two fire types lol) so if I want to enjoy what Sinnoh has to offer I have to play Platinum. Platinum fixes most of my problems with DP and keeps or improve on all of the merits of Sinnoh so we’re good there.
Gen 4 in general has some hit or miss designs for me, and I find myself forgetting a lot of them frequently, despite the fact I started with Platinum. Some of the new evolutions for old Pokémon look great, but then Lickilicky for example looks like complete trash. Definitely not the best roster of new Pokémon, but it’s okay.
Cynthia’s overhyped, she’s basically just female Steven Stone with a much more threatening team. This is okay, but it won’t be until next generation that the champion also happens to be a decently fleshed out character with clear backstory and a lesson to teach the player outside of battling. Wish they’d done this sooner.
By far the worst thing about this generation is the main story of HGSS. Don’t get me wrong, the games are presented absolutely beautifully, but this game’s main story is trash. It has a slightly worse version of the notoriously awful gen 2 level curve except with modern mechanics. Grinding is terrible because of the extremely weak wild Pokémon, and if you want to use more than 1 or 2 Pokémon, if you like to go into gyms with levels matching the gym leader, you’ll have to grind a lot. I found myself grinding my team for an hour for every gym between gyms 3-5 the last time I attempted to play this game, then got through 6 and 7 because for some reason their levels are weird. Once I got to Clair and realised how much grinding I’d need to do (probably several hours worth) I quit. It’s a real shame that games that look and sound beautiful can’t play better. Instead it tries to take my attention away from the train wreck of an adventure with gimmicks galore.
That’s all I have to say about gen 4. To summarise, Platinum gets a really solid pass but isn’t the best the series has to offer imo, DP are obselete, and HGSS is a really big shame.