Furthermore, the semantics of a language should be tailored for its target. Some execution pattern works well on the JVM, some don't. Same for javascript and ot

Furthermore, the semantics of a language should be tailored for its target. Some execution pattern works well on the JVM, some don't. Same for javascript and other targets. Inventing whatever semantics you have in mind without considering how it's going to be compiled is a recipe for slow languages.