In my mind the only thing close to a solution for Disney/LFL is to move entirely beyond the existing characters, so at least there will be one less factor that comes with a lot of emotional baggage for fans.
Or, you know, they could have treated the legacy characters right. Never getting to see the big three reunited just one more time on screen will always be unforgivable. That is one area the ST bungled from the beginning.
To your point, I agree and think a lot of the fervor will die down once the original cast are done post IX.