Because module import is hoisted, does this means that all the dependent modules will be loaded one after the other (Or together), and only then run the actual code?And what about concatenation? Is it even possible?
There is no standard for concatenation but there will be. In the mean time all of the transcoders have support for concatenation. They create es5 bundles.
Another possibility is to combine several ES6 modules into a single one. Not sure how practical that is, though.
In browsers, loading will be handled similar to AMD modules (=asynchronously and all modules are loaded before the module is executed).