Kroak nerf is a huge hit. Probably won't be viable any more in competitive play unless people start using the Realm of Battle rules and every wizard learns 7 new spells each game.
Astrolith Bearer is a big hit. Having to keep wizards near the banner limits your positioning options.
Starseer change is very interesting, but I'm not sure he is worth 200 points. You can generate 5 extra command points in a game, but the possibility of giving your enemy command points is a big risk. You could just buy 4 command points and have them immediately when the game start. If you need a wizard then you could bring a Starpriest and buy 2 guaranteed command points for 180.
Ripperdactyls are... about the same? Before 2.0 they could generate 2 hits per attack, now they generate 1-3 hits per attack. The average is a bit higher, and the max damage is higher, but now they can swing low.
Engine of the Gods summoning terradons that could immediately move and drop rocks was a dumb mechanic and I'm glad it was nerfed. Hopefully this makes stacking EOTG significantly worse because I hate the idea of people bringing 4x EOTG lists.
The topic of "Choice of generals for Seraphon" also bothers me a bit.
The current rules make picking any other general except a Slann kinda pointless, since summoning is so important for us, why would anyone play a list without the Slann being general?
A 260pt wizard with no spell lore, only 7 wounds, that sacrifices his 3 spells to summon 60pt worth of skinks every turn is not very useful. Seraphon summoning has a high opportunity cost and vulnerable to being rushed down.
This could just be my experience but competitive games are often determined in the first 2-3 rounds and don't often make it to round 5, so the value of summoning usually doesn't factor into tournament play.
Slann make very strong generals but they are limited by the fact that we don't have a spell lore. Mystic Shield and Arcane Bolt are both much worse than they were before, and you can only cast one endless spell per wizard per turn. I think the main uses of a Slann are to take Vast Intellect, to boost the EOTG, to fill out battalions, 3 unbinds from anywhere, and give you the option to pivot your gameplay to a summoning attrition style.