I like the idea of making /x the default, and I think it may actually make learning regexps easier for a newcomer.

I found non-literal white space strange in regexps also, but that's mainly from having used sed, grep, etc., for umpty-ump years. If you're just learning the language, I think it's a lot easier to understand something like:

A regular expression is formed from one or more elements that are processed in sequence, much like statements and blocks are executed. You may line up these elements any way you like, since white space is not significant between them; you may use comments freely, just like the rest of your code.

Then it doesn't seem weird to use \s+ to match whitespace. It makes it clear that regular expressions are much closer to code than to literal strings -- the only other place where white space is interpreted literally.

When I first learned Perl REs, I breathed a sigh of relief when I read that all \ specials are alphabetic. I think being told that I could line them up any way I wanted would have been the icing on the cake.