Your opinion on the weather system
Here is my take:
Pros - shift the game back to catching instead of raiding.
More Pokemon diversity based on the weather instead of just local biome.
Cons - I think they over did it with the weather spawns. It's too easy to get a high level high iv Mon now and no real need for grinding. Also with lower levels now catching high level Mons there is real benefit to leveling up. I think they will tone it down a bit soon.
Answers
I think it gives good build in variety, although where I am it's nearly aways sunny, and it's already a fire and rock skewed biome, I have enjoyed the increased frequency of grass types and charmander. (I just caught a perfect charmander!). I'm sure this will continue to get tweaks. However, with stardust having been such a premium item in shortage for so long I can see them overcorrecting for awhile before they rebalance. Remember, in the end this is a "gotta-catch-em-all" game, not a winner-loser game.
I like it. I'm waiting for partly cloudy weather in particular to see and catch some rock types but with the winter around the corner who knows when that will happen. Due to the water biome I don't get that many rock type pokemons where I live.
However thanks to cloudy weather I got 25 level Machamp with 93% IV (14/14/14) but the most exciting part is that for this Machamp raid six people showed up which rarely happens in my city.
I like this feature in theory but I can see it being very frustrating for people who are indoors and want to set up a Lure/Incense, assuming it's even accurate. Especially if it goes on for 24 hours and you miss your streak. I get wanting to minimize liability, but I'm not sure if this is the best way to do it.
I like it a lot, although it may be a bit too powerful in its current implementation. On cloudy days like yesterday here, it was extremely easy to farm Machop and several 100% ones spawned. I didn't have one before last night so I'm not complaining, but they may want to tone down the IV boosting a bit.
I absolutely love how much weight it puts on going out and catching pokemons. It's making it super easy to get good pokemon compared to how things used to be and that might be bad in the long run, but for now I'm excited no matter what weather I see. The possibility of high IV and >L30 wild catches is just too much to resist.
EDIT: I'm also loving the diversity weather has introduced and I hope it never goes away. It's just so much more interesting when 9x% of what you see when going out isn't made of the same 10 species as always.