[denis1]

Well Martin also worked on scalac, with all its warts & problems, so you can't say that it will be better just because he's also working on it. :)

IMO much more important is the fact that Dotty is being developed after several years and iterations of scalac. Ideally this would mean that the problems to be solved, and the different ways to solve them are known. Dotty can do this without having a large legacy inherited code base. To me this is more important.

[doikor]

I think one of the best things about Dotty is that they now have a proven theory that the language works on top of (DOT calculus http://scala-lang.org/blog/2016/02/03/essence-of-scala.html). This has allowed them to remove some unsound things (and work around others in a sound way)

[joostdevries]

Have you heard any of his presentations on the new compiler architecture?

I'm incredibly impressed with the stewardship of Scala: they did a thorough assessment of the strengths and weaknesses of language and compiler and are working on a complete refoundation of the language semantics and a rewrite of the compiler while also steadily progressing along a multi year roadmap for the current compiler.