Yep, I fully agree. At the tail end of Sarek’s life we learn he loved Spock. He doesn’t tell or show Spock ever, which would qualify him as a terrible parent by human standards but he’s a Vulcan so maybe that’s not how he should be judged. What Sarek also doesn’t do is end his feud with Spock which I think is a perfectly good standard on which to judge a Vulcan parent. So while I love Sarek as a character he’s a bad dad.
I also think it’s fairly weak overall but there are some really great outstanding episodes. Blink of an Eye, Counterpoint, Scorpion, for some examples. And I also agree that the worst Voyagers are really very bad, but are they that much worse than other series’ follies? Is Threshold worse than Code of Honor? Sacred Ground worse than Turnabout Intruder? Fair Haven worse than Profit and Lace?