I understand the metagame quite well and I know that new movesets and things like that are supposed to be a given. However, we cannot agree because we have different views on competitive value. While it is true that this is the way the metagame is supposed to be if the set your using is uncompetitive in every way except for taking on a top threat that is bad for the metagame. Take what you ignored in my post. Golduck can combat sun with it's Cloud Nine and water typing however, what else is it good for besides that in ou. Nothing. There are plenty of other Water Types that can be abused than Golduck yet people still use it for that single aspect. There's something very wrong with that.
Concurrently, Magneton in GSC was only ever used to counter Skarmory, and the subsequent Blissey Skarmory combo. Golduck isn't useless, and neither is Magneton (or Magnezone). They both can fit the team well. But they're only used admittedly for those specific attributes; Cloud Nine and Magnet Pull.
Skarmory or Blissey weren't banned on the premise that because it was so dominate, it was invoking reactive actions from players like having to resort to, as you put it, "unviable" alternatives like Magneton. People accepted Skarmory and Blissey for what they were, they accepted the methods they had to deal with them, and the played the game.
Whether or not the Pokemon in question has an alternative use is irrelevant.
On the topic of the weather's dominating the metagame being "perfectly fine" I don't think anyone could agree with you. Another way to overcentralize is to water the metagame down to specific pokemon. As you so clearly stated the weathers do just that. Every other team you see is some kind of weather team and yes it does make it very difficult to non-weather teams to flourish. Also sand never really dominated gen 4. Granted it was a very viable however, it never really took the metagame by storm to the point where you see them every other battle. That's the most major reason people were perfectly fine with them. Now in gen 5 we have 4 weathers completely dominating the metagame. You see some kind of weather every other battle and it just doesn't make things fun at all. It's overcentralizing and it needs to be tested.
In RBY, the generation was centered around what, 8-10 Pokemon? Outside of Mew and Mewtwo, which were banned, there were I believe 81 fully evolved Pokemon total. The game was inherently "overcentralized". Players didn't say "Oh, this sucks. I want to use Dodrio. Lets ban Zapdos and Starmie and Gengar because they're obviously too good and hogging all the action." They dealt with it because it was competitively understood that that's just how the game is.
Fast forward now to Gen V, we now have a similar set of circumstances. While we have plenty of viable, powerful, OU Pokemon to choose from regardless of what weather condition we're in, we do have four dominate playstyles that focus around the four available weathers; some more dominate than others.
But rather than deal with the problem, people suggest we ban to fix the problem?
I'd also like to add that Mew and Mewtwo were only banned because they didn't have a choice. Psychics were really strong as it was, and Mew and Mewtwo especially were the cream of the crop. You couldn't touch a player using either unless you ran one yourself.
Two Pokemon compared to four playstyles, with five Pokemon to choose from to invoke them, along with a great variety of Pokemon to use within the playstyles, and moves/abilities to counteract them (Cloud Nine, Rain Dance, et cetera). You get the picture.
I actually do agree with you about peoples views on bans. Not everybody wants something gone. It could be from a lack of experience or a love of the pokemon (I did alot of research on Reuniclus to help find checks and counters.) and so when things get banned someone's gonna get pissed and wonder why. It's a hassle but bans need to be done. Bans happen specifically to make the metagame more accessible and fun. If bans didn't happen we'd still be using inconsistent and drizzle would be even more of a pain. Latias would still be running the metagame of gen 4 and nothing would really be fun anymore which is what the game is supposed to be. Fun, a game, enjoyment. If we just "suck it up" and let these things run the metagame not many would be playing the game or at least not with that insane ban list.
I don't agree with that particular philosophy.
When you start using "fun" as the moral ground for decision making in a competitive community for anything, the logic behind the decision making deteriorates because everyone has a different interpretation of that word.
You can assume no one would play, but I disagree. This philosophy only just changed halfway through Gen IV. If what you said is true, we wouldn't have had a player base all this time.