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I tend to agree, but realisticaly, how long can they drag out the LTOTS battles? No enemy has lasted longer than about 5 years (in universe) since the Clone Wars. The "Empire" doesn't really count because the leader changed every 5 years or less.
Admittedly, with the LTOTS comic coming out, it seems that they're preparing for a somewhat longer run with these guys as the villians, but that doesn't mean its going to last for much more than another 10ish books. Which is about the lifespan of any good villian in-universe.
Also, even if the LTOTS do stick around for a while, there's no reason there can't be explorations of other bad guys within the same period. Look at I Jedi, the Corellian Trilogy, Darksaber, Planet of Twilight...etc. All occur when the Empire is still the major villain, but that part of the conflict rarely (if ever) appears. There's plenty of space for them to have multiple villains at the same time. Especially if there's no galaxy-spanning threat (which is apparently their intent for the next little while).