General remarks about bare /.../:
I guess the reason why some people support /.../ is because "we have seen it in other languages".
However, we have to remember that Swift is different from other languages in many senses.
First, (as mentioned repeatedly in this thread,) we can define prefix/infix/postfix operators containing /.
Authors simply think it is enough to change the syntax rule of Swift, but the fact that certain number of projects will be broken has come to light.
Second, regex in Swift may differ from ones in other languages.
Although this is out of scope of this pitch, it is related still.
Such feature would confuse some folks especially from other languages.
Let me quote my opinion from pitch#1 thread:
Lastly, Swift has sublime philosophy (I hope).
I agree that /.../ is simple and easy to write.
However, to be simple is not enough to be good in Swift.
I want to quote Mr. Lattner's utterance:
/.../ will certainly break Swift.
/.../ is not Swift's.
Does Swift have to borrow the syntax from others to break itself?
Will we get more benefit from /.../ than loss from it?
Think different.