I had some plans to play with controller, but when A17 is in final and pimps move to A18. Stuff that you mention actually made me rethink. Hope they fix these.
There are actually more controller issues than I mentioned, and I did report them in several of the point releases, but none were ever commented on or acknowledged.
That said you can pretty much easily work around all the issues, and we've been playing on both our systems here with controllers for 3 years now.
My temp fix for the bank down was to split the touchpad on the ps4, and in steam bind the left side to c to bank down when flying. Sometimes the steam keyboard has issues, but you can usually just close it and reopen it to fix that. For targetting the spotlights n such, I just use the mousepad on my kb tro select it... its one of rthose things you set once and don't bother with again, so its not a huge issue.. is just annoying.
There is also something weird going on when using the shotgun... if you select reload using it, sometimes it reloads, and sometimes it reloads AND opens the crafting overlay. its easy to just close it again, but it is annoying ad really breaks concentration and immersion.
We play on 2 4k tvs from the couch, and using wireless keyboard can be a pita sometimes, so controllers are our go to choice.
None of the developers that reply here use controllers at all, so the issues aren't as glaring to them.. the worse issue though is not having the run toggle on vehicles.. especially the bike. After 5 minutes of mashing the stick down to pedal faster, or 10 minutes going faster on the motorcycle to a far quest poi, your thumb starts to cramp up.
One of the developers SERIOUSLY needs to try playing with a controller for a few hours with vehicles and electronics to see why I keep bringing the issue up... on steam it is advertised as having full controller support, and if they can't/won't fix it, it should be advertised as only having partial controller support.
Controller support was 100% perfect in a16.. a17 broke some things, and added some new issues (like the gyro control issue)
I don't think the controller flight has banking at all either... auto banking when turning (like in a plane) would probably be the best option.
Part of the problem is new additions and controls aren't really explained anywhere for a lot of items. There should be a popup window for items the first time you use them showing the controls and how they should be used.. not some encyclopedia entry you have to hunt for first. (Other games do this, and it works very well to train newer players, and most of those aforementioned games usually also have a game option to turn tutorials off.)
Thats really more going gold polish work though.... but the basic functionality IS a big deal and should have been done before each stable release, IMHO.
Imagine if functions didn't work using a keyboard.. the forums would go crazy if crouching or aiming a gun didn't work in a stable release.