While it's true that turrets can be set to forward fire and gimbals can be fired forwards without targeting, it doesn't negate all the other stuff. A ship that relies on a combination of laser turrets, gimbaled cannons and seeker missles is basically left with some half damage fixed lasers, some incredibly hard to use 3/4 damage cannons and a few basically unusable missiles.Yes, i know, but still gimbals and turrets can be used as "fixed" to a degree, albeit with lowered damage output.
And once spotted it's hardly possible to ever go incognito like it was before.
You might not be able to go fully incognito, but you can definitely ignore a significant amount of fire from most weapons. Granted, most players that use KB&M controls have it quite easy with fixed weapons, but even they can be difficult to use with non-hitscan weapons like PAs as the player would lose access to the leading target reticule. There is the issue with AI being near 100% accuracy with fixed weapons even without target lock to help with leading, but that's an AI issue rather than an issue around the mechanics themselves.