Dojo 2 has been in the works for quite some time. It is finally at a stage where most of the packages are in either alpha or beta and can be tested.
You can find more information about the status of each Dojo 2 package here.
SitePen has put a lot of work into making Dojo2 stable and powerful for developers. Dojo2 is all written in TypeScript. SitePen has also been very active in the TypeScript community and providing feedback on features and capabilities. The Definitive TypeScript Guide is still a go-to reference for anyone working with the TypeScript. There is a neat blog post here on multi-platform distribution with TypeScript.
Hit me up with any questions, thanks!