Meh, I never saw Sektor as that much of a big deal if he was gone.
In my book, he was always 1 of the many characters that could be interchangeable / swapped out for other characters, in the next game.
I thought the same to be true with Kitana and Kung Lao, but apparently NRS sees it otherwise.
According to MKX, if Scorpion, Sub-Zero, Raiden, Liu Kang, Kitana and Kung Lao are in the next game, every other Klassic MK character is interchangeable from game to game.
At least that's the general feeling that I got from it, given that NRS wen't out of their way to make Sub-Zero and Scorpion human again, and they also went out of their way to make Kitana, Kung Lao and Liu Kang's default costumes the human costumes, despite their default costumes not being canon.
I suspect that in MK11 NRS will turn those 3 other characters that cry-baby fans must have (Kitana, Kung Lao, and Liu Kang) into humans, and that dead characters like Kabal, Smoke, and Jade will be swapped out for Mileena, Quan Chi, and Baraka.