I’m less concerned about removing F-bound type parameters, than teaching beginners alternatives.
F-bounded polymorphism parameterizes a type over its own subtypes, which is a weaker constraint than what the user usually wants, which is a way to say “my type”, which you can’t express precisely via subtyping. However typeclasses can express this idea directly, so that’s what I would teach beginners (even though there’s a bit of ceremony to deal with in Scala 2).
I wrote a tiresome blog post about this a long time ago. TL;DR is the paragraph above.
rob