Oh, so there IS an official thread for it.
And I found it on a day when I'm in a terribly pissed mood, so in comes long rantish post about how bad G/S/C was.
First of all, let's start by pointing out something: GSC might have been a game with a lot to do, but honestly, you take out Kanto and there's next to nothing. The most powerful Pokémon in the region is level 50, a feat easily surpassed by the wild Pokémon of Mt. Silver (which is ridiculous if you ask me). Besides that, the most powerful Pokémon is a Dragonite, which shouldn't even be there because it's level 50 and not 55.
The difficulty curve of the game was made by a freaking two year-old. At least Kanto made it sort of hard if you picked the Fire-Type starter. (But most critics would argue Hoenn and Sinnoh were worshipping at the altar of Blaziken and Infernape respectively...which is true. However, my argument is that Game Freak should've realized their mistake at Johto instead of continuing to make it over again, and, especially in the case of Hoenn, much worse for the future generations)
If you picked Chikorita as your starter, you were considered one with quite the gutspah, since no gym in Johto AT ALL favors picking it, it's the worst starter offensively, and unless you hop on the bandwagon that is Alakazam, you're starving for a support fighter that can help Chikorita stand on its own four legs and weather the assault of multiple resistances and having 3 of the 8 gyms--the first two being the game's first two gyms--score super-effective hits on it.
There is little to put in GSC's defense other than the odd rare and useful Pokémon that was either found in Kanto or was version-exclusive, rare, and in a hard-to-reach area.
My biggest problem with Johto was it literally had to hump Kanto's leg and ride its cotails. 90% of the useful Pokémon found in Johto were original Kanto Pokémon, and the 10% of the useful Pokémon found in Johto were legendary or absurdly rare, and in some cases, evolved from Kanto Pokémon (Kingdra and Blissey being the best examples.)
Speaking of cross-generation evolutions, that's another thing that Johto horribly failed at, a problem that Sinnoh fixed quite nicely in my opinion; the overabundance of really mediocre, one-liners that had no use to anyone, were absurdly rare, and weren't worth the ridiculous effort put into them to add them to your team. Sinnoh gave much-needed evolutions to ugly ducklings like Gligar, Aipom, Yanma, Togetic, and others.
One thing in Johto's defense that I'm sure will be brought up in a lengthy quote-happy reply by a Johto fanboy is the argument of "Johto pokes sucked then but are super-duper-super-special awesome now." Sure they are now, but they sucked back then. Such suckage has put a nearly permanent bad impression of the game to me.
Frankly, Johto needed Kanto to prevent itself from being a total and complete failure. And, I will point out in defense of GSC; the Kanto remake was brilliant, but honestly, my arguments lie in Johto, because this is the new we're talking about, not the old. If I wanted to talk about Kanto, I have Fire Red and Leaf Green to critique, thank you very much.
Practically everything about Johto sucked. A lot of its Pokémon either are still utter garbage today or were until Sinnoh breathed some life into them. Those that aren't utter garbage were extremely hard to obtain, or were obtained in Kanto, which fuels my argument of "Johto needed Kanto to prevent itself from having Game Freak look like they made asses of themselves, making a ridiculously mediocre follow-up to an iconic piece of gaming history." And I know a lot of you who post in this thread don't want to hear it, but that's exactly what Game Freak did. Compared to Red, Blue and Yellow, Gold, Silver and Crystal were incredibly mediocre. There was no real story like there was in RBY, as you didn't feel accomplished having beaten Team Rocket the final time in Johto (and I'm sure the one Rocket member you fight in Kanto is a total accomplishment to have under your belt, beating a level 34 Golbat.). The Gyms, the Elite Four, and the Pokédex were the only means of accomplishment. After you've beaten Red, there's little to do other than what you've been doing.
Speaking of Red, he was filler and was done absolutely horribly, as were the Kanto Gyms. The Kanto Gyms offered Pokémon that were all terribly weak in comparison to the Elite Four. It was like the game says "OK, you've beaten the Elite Four. Now we put you on Easy Street", because honestly, after you've beaten all the Gyms in East Kanto, the rest of it feels more like a chore than a challenge. The difficulty curve in Kanto was laughable; most of the Pokémon there were 40-50, then Blue comes up with a well-rounded party 8 LEVELS HIGHER. Then, you go to Mt. Silver, start seeing wild Pokémon whose levels are higher than any of the Gym Leaders AND the Elite Four, then fight Red. As if the 8-level jump between Blaine and Blue wasn't bad enough, now you have to deal with a 21-LEVEL JUMP between Blue and Red.
Seriously, Johto was done so horribly that those arguments were off the top of my head. I could probably point out more parts of the game where they horribly failed, but I'm too miserable to give a rat's ass. Besides, I'd piss off those nostalgia junkies.
GSC had its selling points, sure. You could easily beat the game; just pick Cyndaquil as your starter and do nothing but train it 3-4 levels every Route you travel. Good game, yeah.
There were so many bad things about Johto that I just can't think about a remake without having to remember all of those things. Sure, the remake would likely patch them up (Such as giving you a Razor Fang / Claw at one point in the game), but honestly, the Pokémon needed their abilities and evolutions to make them viable, and Johto needed Kanto.
Bad idea is bad, period.
EDIT: Johto's best selling point was brought up to me by a friend of mine. I will admit that Johto has the BEST soundtrack of ANY Pokémon game. However, a remake would likely only damage the game's legendary battle themes (though admittedly, hearing remakes of many of the themes piques my interest in a remake), which adds fuel to the fire of saying how bad a remake would be. =\
