Just had this pop up on my radar, so... Discovery is effectively at least three or four different shows. You can't really judge whether you'll like one season by watching a couple of episodes of another season.
I've watched all of Discovery, rewatched the first two or three seasons, will rewatch the rest, and I'll do the whole thing again, because I've bought the blu rays. (Of course, I've bought all of Star Trek on DVD or blu ray.) From the perspective of a fan since the early '70s, Discovery is a breath of fresh air and about as purely Star Trek as a show can get. Also, if you don't care about how TNG flipped the Romulan and Klingon cultures so that suddenly it's the Klingons who care about honour, if you don't care about the changes in the ways the Klingons, Romulans, and Andorians look from TOS through Enterprise, you don't get to complain about the changes in Discovery.
Enterprise and Nemesis proved conclusively that Berman Trek was played out and audiences didn't want more of it. Discovery had to be different to survive and to restore Star Trek to life. It succeeded.
What's wrong with Michael being Spock's adopted sister? No one knew about Sybok till he showed up. Spock's not exactly chatty about his family.
Nobody knew he was trying to take Pike to Talos III until they realized they couldn't change the ship's course.
Nobody knew who his parents were until they showed up.
Nobody knew he was betrothed to T'Pring until he experienced pon farr. (Although SNW retconned that. People complain a lot less about SNW than Discovery, strangely enough.)
Nobody knew he was going to sacrifice himself to save the Enterprise in Wrath of Khan until it was too late.
Nobody knew he went off to Romulus to support unification until he popped up on camera footage.
Not telling anyone anything, even when it would have been the smart thing to do, is what Spock does. That he had a human adopted sister is hardly the biggest surprise. Not to mention that an episode or two of Discovery did more to flesh out Sarek and Amanda and their relationships with Spock than anything since, oh, maybe "Yesteryear."