I’m a bit worried that this introduces unnecessary complications to students, as they then need to keep track of different Scala dialects - this might be daunting to a pure beginner. Also I’d like to keep Scala one language rather than a set of sub-languages (c.f. the rationale for principled meta programming instead of exposing the compiler to allow deep language modification creating dialects).
An alternative solution would be to offer warnings that can be turned on and off for some carefully selected things, such as mutable classes with exposed, non-local mutability.
See also Why scala is still keeping var in it? - #10 by Mahadi - Question - Scala Users