Gen 5 negatives
No genies in bw2 and dream radar is annoying to get and playthrough.
All kind of commemorative achievement things were removed like symbols for subway bosses ( gen 4 had trophies to for battle tower so we are not counting those ) stylish ribbons, and stars on trainer card, without looking up the colour upgrades there is no way to tell a trainer level by merely looking at the card.
Alot of medal requierments are ridiculous and add no challenge or fun to the game such as passing 1000 people or doing a funfest with 30 people, the medals idea was great to make you try everything the game has to offer but the final version of the product is not to great.
Musicals are contests with no actual substance or challenge and are utterly boring
Movies are better than musicals but still not that captivating they are way inferior to pokeathlon and gen 3 and 4 contests.
* Forces of Nature: Yeah, the Dream Radar was such an odd peripheral, especially making it the only way to get the Forces of Nature in B2W2. Would have at least liked it if they included the opposite version member in the sequel so if you only got one version and its sequel you'd have both Thundurus and Tornadus to get Landorus in the original.
* Lose Symbols, Got Medals: Sad we didn't get a Battle Frontier (though would have been a neat alternative if each of the Subways awarded something similar, like maybe a stylized Subway Token; guess also be neat if White Treehollow and Black Tower maybe also have out something). However, even if not all the Medals were interesting (and some are not even obtainable, blech), I do like the Medals and found them fun to collect, even when you get ones you didn't realize you qualified for since you just went out exploring. Also, though its not quite the same as a collectible, I found filling out the Habitat Lists to be a fun collection thing; at least a more fun way to fill out the Dex (and likely laid the way for ORAS's DexNav).
* Musical Theater: Excuse me sir, sure Pokemon Contests and Pokeathlon had deeper mechanics, better rewards, and a proof of your completion of it... but can you put a top hat on a
Snivy or
Wailord? I THINK NOT! Musicals 1, All other side activities 0.
Okay, joking aside, yeah, Musicals did feel pretty flat. Not to mention Musicals were also yet another feature which had parts of it cut off because there were special musicals only available via through the Global Link.
PokeStar Studios I was more interested in the concept than the execution. Kind of wish instead of just a scripted battle they had sort of an in-game adventure where you played out the major scene of the movie with the scripted battle(s) part of it; but maybe that was too much of a hassle to figure out how to score. I've always kind of wanted to write out a full script, or at least a fanfic, of the PokeStar Studio movies. I also like all the easter eggs like what the movies were based on, how the titles (at least in the original/on the posters) are in difference languages, and when you get your own room there's a book with a whole list of well known stories but Pokemon versions of them (which, being a lot of them were puns or based on stories known by an American audience, I wondered if other languages had their own listings...).
Hgss cons
No story in kanto which feels bit dry and empty they could have expanded the rocket giovanni and silver storyline into kanto.
Customisable safari was a fun idea but the final version of it is horrible, having to wait nearly a year for some pokemon is just insane what where they smoking at the time lol.
Repeat battle frontier from platinum feels a bit cheap, could have at least brought back emerald frontier instead which was awhile ago and would have felt fresher in a gen 4 game.
Gym leader numbers are way to awkward to get without online research which you should not need to resort to, way it worked in emerald and platinum was fine.
Kanto Story: Kanto didn't have an overarching story, rather it was more focused on little personal stories. Kanto was pretty much just a bonus, giving those who played Gen I the opportunity to see how things have changed 3 years later. I guess they could have had made a story revolving around Silver trying to improve himself instead of just making it one bonus tag battle of you & him vs Lance & Clair. However I don't think Gen II Kanto really needed it especially after cleaning up the remnants of Team Rocket.
Customizable Safari: Yeah, the waiting a number of days before a Pokemon appeared thing was a decision I didn't understand. Aside from getting the Pokemon there's no other reward, it would be quicker to just transfer a Pokemon you need up from Gen III or trade it from DPPt.
Gen IV Battle Frontier: A bit disappointing but I understood why they did it. Battle Frontiers take a LOT of time to make and would feel just a waste for Gen IV's to just be in Platinum when it wasn't going to be the last game in that gen, and excluding it from HGSS would feel like they're offering less content in HGSS in that regard so they just transferred it over as a bonus more than anything. MAYBE they could have made some things different like gave the Brians new designs, changed the Plates back into Symbols, little things so that it's the Gen IV Battle Frontier but it's own style of it.
Gym Leader Number: What? Was it not obvious to get Lt. Surge's number you had to first clear the Kanto Power Plant for him to then visit it on Friday morning while having Pikachu walking with you? I mean, come on, they couldn't be anymore obvious.
Yeah, some requirements were weird though others were funny or got funny dialogue. I would agree Platinum was probably the better of the three even if you couldn't battle all the Gym Leaders everyday.
Platinum cons.
Id say the game basically has none except for a few not massively important things.
Well if I was allowed to add one: The Villa was a neat idea but kind if disappointing as aside from decorating it there was really nothing else to do with it, especially after reading all/most of the visitor dialogue. Like, if it's my Villa, can't I do things like maybe hold certain parties and have special battles, get unique trades & items, etc..
Emerald cons
No second improved league like FRLG makes it a bore and very hard to level grind and on top of that you can only battle Steven once in the whole game rather than once in awhile at least like the gym leaders, and there is no postgame area with decent level trainers to level grind so its a mercy you can clone in emerald otherwise leveling stuff for the frontier would be a nightmare.
Not being able to battle the rival later in the game sucks, they could have changed this since RS.
Emerald has so many cool islands from mirage to all the event islands and the fact to most of us never got to see them really sucks,
Sad that RSE didn't do that, but thankfully ORAS mostly remedied all these... and then didn't include the Gen III Battle Frontier and Gym Leader rematches...
I confess that I’m being rather nitpicky especially when Fly is not a bad move at all, and when I do have it it does see a decent amount of usage; it still annoys me greatly because of how it limits my Pokémon (move) selection. There’s worse things to be annoyed with but this is just little thing that makes me agitated.
Well, at least it's no more a worry Gen VII onwards.