Hi! The size of the Sector is what it is mainly for gameplay reasons, not performance. How long it takes to fly around, to explore everything, to find certain things that there are only a few of, and so on. In my mind a larger Sector would not be improvement, though I understand that this is subjective (and reserve the right to change my mind!). Just, wanted to make the general observation that the limiter for sector size is not actually performance, and that I don't want to fall into the trap of "larger sector = better".
(I get your point about the new traversal options, but, as a counter-point: those were made to bring movement/travel closer to what I think works best, and making the Sector larger would just be working against that. But, well, fine-tuning the game like that is one of the things mods are great are for!)