Star Trek: Picard may open the door for some retconning.
Star Trek has been around for nearly 70 years, and some things need to be retconned. That’s not exactly a hot take, there’s a lot of inaccuracies and inconsistencies with the Star Trek timeline. After all, why wouldn’t there be? Each show has had its own showrunner for the most part. While each era was largely oversaw by a few people, each series had its own leadership. No series was ever micomanaged so much that there wasn’t something that fell through the cracks.
The Klingons having three different eras of foreheads in only a hundred-plus years is just one thing that comes to mind. There are others that just don’t make any sense, like Spock having a sister, Jean-Luc Picard being an android, Neelix dating a two-year-old. Stuff like that could be erased from existence and most fans would be fine with it.
Who knows what the second season of Picard may offer.
Season 2 of Picard could also deal with the Kelvin Timeline.
We’d be remissed if we didn’t mention the possibility of the Kevlin Timeline coming into play as well. Technically it’s not an entirely different universe, but a different timeline that fragmented out from when Spock went back in time. That entire timeline could be snuffed out of existence if the big-wigs at ViacomCBS wanted it.
They could also bring those characters/actors into the prime timeline as well. It wouldn’t be the first time Star Trek created an out to bring a character over into the prime timeline. Granted that was for Harry Kim when he died, and the other version of Voyager was able to rescue a doomed version of Voyager’s Kim, and a young infant Naomi Wildman.
Don’t even ask which ship was the original, as no one really has a clue. That episode of Voyager not withstanding, the introduction of time travel, and the return of Q have opened up the possibility of fixing some long-standing issues.