Why should I wait because Python and Ruby are already there? Perl6 is not just a cleant-up perl5 with a few added features. It is a redesigned Perl
That that it needs an answer, I will point out that you didn't
answer the question ... (meanwhile, I am psychologically incompatible with Python, so you don't have to worry about it!).
Having somewhat of a project management and software design background (err, acquired in weird ways, but nonetheless), and adding empirical evidence .. it does appear that Perl 6 is attempting a HUGE, and I do mean huge BDUF ...
In my personal endeavors, BDUF leads to fatality. As for fragalitiy of interfaces, I do sympathize, although many other languages have survived from very early versions with large-scale changes moving through it with each revision.
If you can't release because you are tracking to a known level of completion, that's one thing ... if you are not sure when it will be done or what it will be when it's done, that's huge -- it's something that you really have to watch out for. Part of software design isn't just making a good interface, it's making a flexibile interface and accomodating change.
OT: To sound a bit heretical, I actually don't care much about Parrot. Sure, it would be nice, but other languages already have fine interpreters. The CLR/Parrot idea is interesting, it could prove useful, but mostly, I am a HLL guy -- and I think in languages not in implementations. The beauty of Parrot will likely to those people who like to work on internals, that's just not me. Anyhow, replacing the VM and the language at the same time may actually be too much.