There are always challenges integrating new features into an existing language, especially if you aren’t willing to break backward compatibility. Java can never completely get away from the verbosity of its youth because that is now baked into the language in ways that they can’t escape. Related to this, it will be interesting to see how much the addition of generics to Go impacts that language. Their rallying call was that Go was that it is simple and compiles fast. Generics are likely to have a negative impact on both of those.

I think it was very impressive how many things Odersky got right in Scala in right from the beginning. The only significant feature that wasn’t addressed was null safety. I am glad to see that is coming in Scala 3. I also appreciate languages that are willing to break backward compatibility to add features. Time will tell if that is really a good way to do things, but it is important for someone to be testing those waters, IMO. I think it is something that works much better in statically-typed, compiled languages than in dynamic ones. The move from Python 2 to Python 3 was a mess, but a lot of that is because Python as a language didn’t help people make the transition.