The inertia parameters are part of the aircraft flight model config, so it’s dependent on each project to specify reasonable values. I find the Asobo planes to be a bit low with the inertia values which makes these models more “twitchy”. A dev could certainly make the flight behavior better.
At the end of the day, different simmers will perceive the flight models differently, so who knows what is best. There are plenty of flight model improvement mods, so apparently others are not satisfied with the values either. But I don’t think there is any simple global change that is going to make every plane fly more realistically.