dskoll certainly has valid concerns, but he turns into a real asshole as the thread continues:
I believe the improvements in speed and memory required to make Perl 6 competitive with Perl 5 are unprecedented in the history of computer science.
This is a ridiculous statement, of course things have been optimized by 95% before. Given the specific explanations given by the devs about the wholly unoptimized state of the project along with planned optimizations, it seems well within the realm of possibility.
I'm not sure what the chip on this guys shoulder is, but it sounds like he just wants perl5. He gives no consideration for the innovation and creativity behind perl6. If he doesn't give a shit about all the advanced features then stick with perl5 for god's sake, it's well proven and it's not going anywhere. But to argue ad nauseam about the impossibility of an "adequate" optimization from a totally ignorant position is pretty offensive.