We are using tuples for everything in our application for performance and compactness. I'd love to be able to replace the 200 or so //msgp:tuple directives with a single flag to the generator //go:generate msgp -tuple.
I suppose this means there'd need to be a new directive //msgp:map, orthogonal to //msgp:tuple in the default mode.
Happy to have a stab at this if you think it'd be worth including. It'd certainly make my life a lot easier!