My take on it, from a low-end machine.
1) Barrel overheating? Do you have any idea the amount of the whines that would come from this? Humidity isn't modeled right, there's not enough low temp at 25k. Real can of worms there, and as discod said "seems like a lot to stop spraying."
2) Who'd see flying brass? No one unless you were in the TA or offline. Waste of code and time IMHO.
3) Cloud layers? Already possible by modifying a file, and wreaks havoc on my old system. I'm lucky to see 8 FPS around A6 in this BETA map due to the humongoid cloud layer over it.
4) Smoke from the guns. This could cause one MOTHER of a FR hit if done on every plane. When attacking BUFFs I'm lucky to get 12 FPS, you want to drag that down even more? OTOH doing it for cannons [37mm or larger, like WBs] would be fine. Few of those around anyway, so when you spotted a small brown cloud from a B-25H or Ju-87G it would be a treat.
5) Hmmmm..... If the explosions were ever fixed [look cartoonish] I might go for this. Right now I like the standard hit sprite, but agree with others that they could be expanded on. If you get major pieces blown off an AC [wings and such] you see it. Albeit they are a tad SMALL. You would have to make the blown off part 3x normal size just to see it. My FR is better spent in other areas, like trying to figure out if Rip just flipped me the bird or not.
One thing many people here forget when asking for more of this or that is people like me. Stuck on an old rust bucket that'll push my 109 along at 18FPS. If you want more clouds, make it an
option. Want thicker smoke for blown-up stuff,
make it an option. Smoke still kills my FR [5 if I'm lucky] as do the clouds. All I see the above doing is chewing up my limited resources. Therefore useless to me in a flying sense as it will not add to, but detract from the game.
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Flakbait
Delta 6's Flight School"For yay did the sky darken, and split open and spew forth fire, and
through the smoke rode the Four Wurgers of the Apocalypse.
And on their canopies was tattooed the number of the Beast, and the
number was 190." Jedi, Verse Five, Capter Two, The Book of Dweeb