Well most of the decisions seem like common sense answers to cover gaps in the original writing of the rules, so no big surprises in there.
The internet-favourite conga line of Scarabs has been killed off, forcing new swarms to be placed in coherency with models that existed at the start of the turn. Well, thank goodness for that! I understand why people wanted to stretch their unit across the board like that but it really was a bit silly.
I was slightly surprised that Lychguard dispersion shields will only bounce hits of AP3 or better. True enough that's how we've been playing it locally, but I anticipated GW allowing the deflection rule to work with their normal save too.
I'd also expected to see the ability to have 2 Royal Courts assign members to the same squad. I've never experimented with that option, partly as I expected it to be FAQ'd out, but I'm now starting to wonder if there are places I could make use of that.
There's still one or two things from the Codex that I feel could do with clarification, but overall this should help clear up a few points of confusion. I'll have to take a few more reads through, but for the moment I don't imagine it's going to change much in my list.