Note I haven't dug deep into everything, this was just my general first impression on how everything was working and slightly using everything.

Wind Physics (and features built around that)

I like this, I think the wind's max setting is crazy and huge but fun if you're trying to go for the "Fly in a tornado" effect, though I just set it too a light breeze for some fresh air. The windsocks on the airports are a nice touch to show the wind blowing and show it's there and not some invisible force.
I think the new "Cross Wind Landing" challenge is a bit tricky. I did it on my second try but still. I think maybe decrease the wind speed a little and move the start point a bit farther away. So it's easier. But it's still easier then flying in 100+MPH winds which means you're in a tornado.

Torpedos

I like this, it's been awhile since we got a new weapon of some kind. I wish you added two and made a 500 lb. torpedo for even more damage. Granted it's easy to make one via XML but still. Also you might want to add the torpedo into the tutorials because they aren't in there so new players will have no idea how to use these. Maybe a combat challenge called "Torpedo training" would help?

Featherfall Squall, (and other bug fixes)

The main bug everyone cared about that was so darn hard to unlock. I spawned at Avalanche airport and unlocked it immediately. I am glad you made that bug fix. I think Andrew missed the joke about Mirage speedway and I sorta liked it being visible only on medium/high settings, making it a "Mirage" on that setting. Though I don't overly mind it's just there. Minor.

Gyroscopes,

Okay, I love this new part set. Now that gyros are official, it renders mods like the Gyro cockpit mod and interesting gyro concepts built in-game obsolete. You could still download and use it but you really don't need to now. The sphere and hemisphere is a nice touch for helicopter LG. Really though it's a tricky thing to get the hang of, and new players trying to decide weather they specialize in making helis will have not much clue on how to use this. I think there should be a helicopter building tutorial personally that's quick and involves the basics of using the gyro.

HUD Display

I made a little section to talk about this real quick. I like the new HUD, it looks sharp. Though it is a little bigger and slightly more annoying when trying to get a close up view of your plane and don't want to see that. Of course you can always press F9 and make it disappear but still. I think maybe add some HUD type options so if people liked the old one, they can have that, or the new one. Maybe add a few more HUD looks like for old planes, futuristic, ect. and you can change this in settings. Might just make a user voice vote on that.

Extra notes,

So far my older designs haven't had a problem or very noticeable difference in flight. I am building a new plane on the beta and I like the performance so physics seems normal (well, still drunk physics but normal for SP).
I honestly think this update is amazing and the payoff for the wait was good. I guess you could call this the gyro update as that feels to be the most important addition to the game in this one. I sorta wish it had more in it considering how long everyone has waiting but beggars can't be choosers. You guy's are doing a great job, and frankly I think this will motivate semi-innactive (not uploading but talking) players to become fully active again. Plus the timing of the update works out.

All in all, i'm happy with it, I wish it had a little more but considering you guy's are working hard on SimpleRockets 2, it's good. I think this is exactly what the community needed and the timing couldn't have been better. I hope you could bump out one more small update just as SR2 comes out but if you can't that's ok. Just my first impression, all happy, no notable major bugs, good job devs!
8.5/10 on this update. :)