IMO, removing features isn't progress at all.
Hi! I wrote a patch for Perl 5 a couple of years ago which added a class keyword. You'd think that'd be an easy change to the lexer and tokenizer, but I had to work around the Perl 4 package separator code—you know, the one that you only ever see in Acme modules, and then infrequently. Yes, that's the same feature that's been deprecated since Perl 5.000.
Now I understand not everyone might ever want a better syntax for declaring classes or methods or object attributes or regular expressions or file handling or function arguments or whatever syntax other people might want, but think about that. Adding a keyword to the language (without even worrying about whether it's doable in a backwards compatible way) requires working around features deprecated since the first release of Perl 5.