The main thing preventing me from finishing the work on decorators is that it is not clear yet wether they will have optional parentheses or not.

Currently the proposal specifies @deco and @deco() to have the same meaning, but there is strong opposition from different people (tc39/proposal-decorators#81).

I propose adding an option to the new implementation of @babel/plugin-proposal-decorators (e.g. optionalParens, or automaticParens) which toggles this behavior. This would have two advantages: it would allow us to ship decorators in Babel 7 and it would make it easier to collect feedback about which of the two behaviors is better.

cc @littledan