I remember almost nothing from Season 2.

Second Foundation's plot and characters were great, I can see we've deviated well past that book. I don't hate the series, but I knew keeping close to the books would be impossible. And it's a shame, because the book Mule is a fascinating character, and so is Arcady.

I never got around to watching the second season. I originally started watching it for Jared Harris, but Lee Pace and the whole genetic dynasty thing really carried the show in Season 1.

Is Season 2 worth watching?

Tried re-reading the books following watching S1&2. Honestly, they made me appreciate the show a lot more. The extra changes & characters have only improved and enriched the universe the story takes place in. Can't say all the changes are good, but they are all better than the books.