It would and has been suggested before but two staff responded Implying they disagreed with the Idea, partially because It didn’t make sense logically. As Shadow said In the thread, you can’t really blow away the sun, or rain or hail for example. It does rightfully remove fog, and In my opinion removing cloudy would work too ( as Shadow also stated ), which Ironically Is not at all useful for what’s being suggested In this post.
This I think would work rather well though:
As seen on Bulbapedia’s Cloud Nine page, It actually Is part of the effect of C9 In the 2D PMD games.
So If C9 could prevent weather being changed at all for a certain amount of time after entering the floor ( or the entire time ), that would honestly be a great way to fix this Issue.
Just to throw another Idea out there, I was told about someone suggesting that Instead of having to hold the rocks, they can be Infinite-use Items that change the floor’s weather to the weather of the rock. This would actually be worse for cloudy and fog though, because cloudy weather lowers the power of all moves besides Normal and fog does that for Electric moves.
Also just because we don’t have Immediate access to fixing their weather, doesn’t really mean the Cloudy and Foggy Rocks are useless ;(
It sucks when the weather gets changed but In any other dungeon that doesn’t have something with a weather Ability they’re as useful as the other rocks. “This makes it mandatory that you carry a Pokemon with cloud nine to get use out of these rocks” applies to all of the rocks that aren’t the Clear Rock.
I get that Drizzle, Snow Warning, Sand Stream and Drought exist but If you’re running a dungeon with others ( and even If some players often run dungeons solo this Is still an MMO so co-op situations should be accounted for ) that don’t synergize with the weathers those bring, you’d have to use the rock alternative. I just don’t think It’s fair to call the Cloudy and Foggy Rocks useless when they still obviously have a use. I know they’re not viable, but cloudy and foggy Orbs still exist, as do Orbs for the other weathers besides ash and diamond dust. It’s mostly easy to avoid dungeons that have weather Ability Pokemon besides Skylift since people often train there ( but for what It’s worth Altaria also spawns on the floors Pelipper does. You can strategically leave Altaria alive for last ).
Nerfing Clear Rock to the same level as Cloudy & Foggy
lol I don’t see how this would work anyway. If the Clear Rock were to only work If the weather was clear then… 
I do think that the Clear Rock could be more Ekop potentially. It’s pretty powerful after all.
ps: not to hijack the thread but on the topic of buffing the Foggy Rock 
Anyway I don’t think this change would be bad or anything, I only wanted to share my thoughts. I heavily agree with the Idea of Cloud Nine locking weather to clear either temporarily or permanently Instead though. It would help all rocks and not just the Cloudy and Foggy ones.