Agreed, the size and scope of the DSL will impact the amount of man-hours necessary for developer experience related work. Resourcing that effort is a separate concern, but one that should be considered for the DSL's viability.
JSX, being a sugared syntax for the React.createElement API, likely doesn't need a team of 20 for editor integration, whereas Angular templating language has more to it: pipes, directives (shorthand and non-shorthand syntax), property bindings, expressions, etc -- and templates need to be evaluated in context of their corresponding TypeScript Component.
JSX, being a sugared syntax for the React.createElement API, likely doesn't need a team of 20 for editor integration, whereas Angular templating language has more to it: pipes, directives (shorthand and non-shorthand syntax), property bindings, expressions, etc -- and templates need to be evaluated in context of their corresponding TypeScript Component.