There is a lot of design overlap. That is the reason why I think we should vision variadics as a whole in its future rather than simply repaint … postfix to a type annotation keyword @variadics. This will only close the doors for some features we might want to add in a future version of Swift.
This seems like an entirely separate feature to me; unless the intention is to go back to the old style of treating function arguments as a tuple I don't see why they should need to be related?
This was my first thought as well: imho it doesn't make sense to discard a good idea because of a vague hope that there might be something better (in, I'd expect, two or three years from now…).
Maybe you could explain a little bit how the feature you are hoping for should work, and why there would be interference?