I don’t buy this “Transpile” thing at all. I’m not writing my next project in TypeScript (for whatever it takes) as long as this sluggish Transpiling is involved, as I’d not be able to perform those micro-optimizations for all performance bottlenecks if all of that is lost during transpilation into JavaScript, and I don’t see any major browser (except Edge, if it gains that share) to ship with TypeScript VM apart from regular JavaScript VM in near future. Sure TS will laugh at JS gaining all new features, that it is enjoying already since beginning, in coming months but it is far from getting first-class seat as long as any moderate enterprise webapp written entirely in TS takes couple of minutes to be ready to run in current browsers.

We all saw how SASS (and later libsass) crushed LESS in no time, if Microsoft really wants developers to adopt TS, it needs to provide a better, native compiler that does more than just “transpiling”.