There are also those who use the mouse exclusively for turning. I personally didn't like playing like that - but that may be due to the fact that I'm used to my joystick. However, you are not enjoying using the mouse exclusively for turning and don't want to get a joystick, consider the above advice from Quantum and Snoo which is to use a combo of KB and mouse for turning - KB for larger turns and mouse for fine control.
I'm not "frustrated" with the community, rather with this:
Minimum system requirements: Windows XP or Windows Vista, 1 GHz Processor (1.4 GHz recommended), 256MB RAM (512 recommended), 3D graphics card compatible with DirectX 7 (compatible with DirectX 9 recommended), monitor capable of displaying 1024x768 resolution, Mouse, Keyboard. Patched to version 1.02.
If this game couldn't be controlled as easily as X2/X3 or similar space sims with the mouse, GOG would be outright lying, which would have completely and utterly pissed me off, and I'd like to prevent becoming more cynical towards spending money here.
I've played FS2 perfectly well for years with a mouse and keyboard. You'll need to up the mouse sensitivity in the game options a bit. Bank, turn, aim and shoot with the mouse and engines, shields, targetting controls etc. are done via the keyboard.
As long as you up the mouse sensitivity the game plays perfectly fine with the mouse, except for the Boanerges-class bomber, but no one likes that ship anyways. I don't have the budget for a joystick, but I do perfectly fine using the mouse for steering and shooting and the keyboard for everything else.