I can’t speak for the core team, but my understanding of the situation is:
The general rule is “no source breaks”. Swift 6 is in the unusual position of being forced to accept some source breakage in order to meet the language’s core goals (safety, in this case for Swift Concurrency), which opens the door to potentially accepting a few more since people will already be dealing with it.
The bar for these is still quite high; fixing serious problems in practice, not just aesthetic or nice-to-have stuff. If you wanted a change like this, I would expect step one to be demonstrating that the problem being solved is one that meets that bar.
Doug goes into more detail here: Design Priorities for the Swift 6 Language Mode
My personal feeling on it is that this change would actually make the language slightly worse, since it would be difficult to remember which goes where with them so similar. But I don’t tend to have strong opinions about surface syntax, so if folks disagree with me I’m not inclined to argue.