Nkululeko I'd like you to tell me why Ferrothorn, Garchomp, Scizor, Gliscor, Reuniclus, Heatran, Dragonite, Conkeldurr, Gengar, Thundurus, or Skarmory's positions would change that much if weather was completely banned.
Ferrothorn is still the resistant monster in the game.
Garchomp is just as much as a threat out of sand than in it, Sub SD is only a Minor loss that chomp can go without and maintain the same position.
Scizor is neutralized by bad weather for it not existing, and even stuff like Jellicent that's used to help check rain might fall, so it might even do better.
Gliscor is still one of the most annoying walls in the game.
Reuniclus is still Reuniclus, it is and always will be good.
Heatran gets the same neutralization as Scizor.
Dragonite doesn't need weather in the slightest, if anything it benefits from SS and Hail not chipping it now.
Conkeldurr is still the best fighting type in the game.
Gengar obviously lies out of weather altogether.
Thundurus doesn't even use Thunder most the time, and appreciates lack of SS Chip, same.
Skarmory still is the best way to Phaze and get spikes up. Team support is there for fires. Hell, Team support for ANYTHING else on this list that loses a resistance from Rain or sun.
So place-wise, 11/20 Mons would stay within the top 20, and probably in their relative locations if all weather was banned. Lets throw in stuff like Rain Resistances and Sand Veil, and we get that weather is influencing, say, 50% of the metagame, and not the drastically overstated 85% that you give.
Now if 50% of the metagame is too much is not for me to decide, and I will not argue on that. I'd just like to see less stretching of the facts, here.