Better, yes, but broken? If $/ consists of multiple characters then it will not function as intented. Consider this as an example:

my $foo = "Camel meme power supreme!";
my $bar = "me";

$foo =~ s/$bar+/$bar/g;
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The answer is not what you'd expect, the string remains unchanged. It seems that brackets are required so that the entire variable is repeated and not just the last character of the variable. "meme" to "me" and not "mee" to "me":

$foo =~ s/($bar)+/$bar/g;

So this translates back into something like this:

$line =~ s!($/)+!$/!g;

/s modifies ., which is not used, so ditch it. You don't need to use /s just to work on multi-line strings, but sometimes you want to.