We've already done what you've proposed. Its name is Garchomp. There's no need to make a complex ban just to save one Pokemon from going to Ubers. Otherwise we'd see Speed Boost + Blaziken and Sand Rush + Excadrill. We don't. The post you linked here is pretty simple too. It falls into the same category as the examples I just listed above. If Dragonite is broken with Magic Guard but nothing else with Magic Guard is broken, ban Dragonite. Simple as that. My proposal isn't banning what is broken, it's simply banning what is uncompetitive. It's similar to Moody, where it makes every game a crapshoot, but not truly "broken." Also, if that were to buff rain even more, which I highly doubt, then if rain was broken then it would be banned. You say "Why is this such a hard thing to wrap our minds around?", but there is literally no benefit other than nerfing an otherwise broken Pokemon, when it is extremely bad for policy and precedent.