Haha, I'm the wrong person to ask. I was fortunate enough to be in a hands on senior role, and I promoted a very light Java++ style, to be learned in a 2 hours seminar: immutable collections, case classes, pure functions, impure logging & exceptions, sparingly used interface polymorphism, recursion, filter/map/flatmap/fold. Scala: The Good Parts. To this day I have not learned the first thing about implicits or type variance, and probably there are many many many more Scala features I haven't even heard of. The biggest challenge was helping the rest of the team avoid writing inscrutable sbt plugins. The plus side, it makes little difference Scala2 vs. Scala3. The downside, some teams may scoff at such a mundane approach.