If they are working on more varied whether conditions that's great, there's a difference between what can be done with the game engine and arena settings and what we'll actually see in the MA's.
Bad whether in the MA's would be a drag once the novelty wore off (kind of like night time), however I would also say that whether would be a key component to special events. For example it would kill immersion for me to run a scenario based on the Aleutian campaign under sunny skies.
Tacking on to Soulyss's and Yeager's points: I think it would be a drag to try and dogfight in dawn/dusk, night or bad weather,
unless there was some incentive to do it. Maybe these things could be incorporated to a judicious degree
and if HTC provided some incentives to keep playing in that environment, it would actually spice up the game.
For instance, maybe some coad could be created that ties earned mission or perk points for attack or bombing runs
while the bad weather or low lighting is occuring. Meaning, if you used the low-light or bad(-ish) weather to mask your attack or bomb run, for example, you would earn double points, precisely because it was harder to do. Then, in order to counter that and create balance, fighter kills, particularly against or during said attacks under those conditions would earn pilots double perks/points too.
Thus, the prospect of earning more points and perks might keep players in-game during those periods, and maybe add some variety to the noonday/bluesky norm.
Anyway, just a thought; maybe it's not practical to implement or would degrade gameplay. Perhaps it could be tried in a testbed arena to see if it would work out.
FWIW