I'm going to be in the minority here: but I strongly dislike the new upgrades to SoK. It reeks of power creep. SoKs are already the "baseline" to which event buildings are compared. 1 FP per 4 squares (ignoring roads). And they are still strong enough that almost all players have them. So why upgrade it? Unless you are going to somehow limit the number that can be upgraded, this just means that so many other buildings are going to be relegated to garbage status.
On a positive note, the artwork for it is beautiful.
Edit: Okay, now that I've had time to think about this, I feel I can better express myself.
It feels rewarding to replace a SoK. Every time you replace one, you know your city just got better. It's amazing! Event buildings replace them and you look and go, "yeah, now I'm getting 3 more FP out of the same amount of squares, plus some goods and whatever else". It's nice. But now... we'll be re-evaluating those very event buildings to see if they are worthwhile any more. That great feeling when we replaced SoKs with that new building? Now we'll be replacing those buildings with SoKs. It feels like we've regressed. Yes, our city gets much stronger, of course, but to go in a circle where it was: SoK -> really cool building -> back to SoK. That kind of circular progression just isn't fun.
Now, I realize that we won't have level 2 SoKs like crazy right out of the gate. At least I hope not.
