I have a feeling they won't know how to fix it. Fixing the issue would involve opening up the full X and Y combined input range, sounds easy right? However, in doing so this will mess with the feel of the 'looking/aiming' control scheme that the first person shooter people like where the right stick acts as a crosshair that moves in a big circle with limited diagonal reach. They must have had those type of players in mind or it wouldn't be messed up the way it is currently.
Not to mention they made the 'look around' instead of 'fly around' control scheme the default. This favoritism towards first person shooter players would also explain why the yaw moves as fast as the pitch, whereas in traditional flight sim games the yaw is slow, requiring you to roll over and pitch for a quick change of direction while yaw is limited to minute corrections. Basically someone had to be sacrificed, either the flight sim people, or the first person shooter people. And us flight sim people are not the biggest pool, if we were this bug would've gotten more widespread attention right away.
The only way to fix it without messing anyone up, would be to either have an extra option toggle for 'full' or 'limited' range in the controls settings, or to hardcode in the limited range for the arcadey fps style controls and hardcode in the full range for the realistic flightsim style controls.
So because of this conundrum, I don't imagine they'll have this problem solved any time soon. They're probably scratching their heads right now wondering what to do. Not saying they can't fix it in a way that makes everyone happy, but I just don't want to get my hopes up. Especially since it's only been flagged and is "being investigated" but hasn't made it to the official list of known issues yet. But I'm just hoping to be pleasantly surprised. When EA came out with Battlefront II, the diagonals were slow at launch, but then after some time passed - they fixed it perfectly. So this isn't the first time they've had an issue with diagonals, let's hope they fix it just as good as they did before.