IntelliJ is a great IDE. Android Studio removed a few things needed by Codename One to compile. It's also really slow... Painfully slow. There are tips to make it "bearable" but a vanilla install of IntelliJ still runs circles around it.
We don't need any of the features in Android Studio unless we want to debug the native Android code (which I don't cover in the book and frankly rarely do as it's redundant).
Providing hints for people moving from Android makes a lot of sense. We made several attempts at doing that but things change on the Android side quite a lot and it's hard to keep up (things also change in Codename One so it's a two way street of problems).
co-founder of the open source Codename One project