in reply to Ripping out Perl internals in Perl6
That being true, you won't have to learn anything new if you don't want to. But that's true now: very few Perl users know everything about p5 that there is to know. That's one of the great things about Perl: it's learning curve is as steep as you want it to be.
No matter what, your concern is premature. Until v6 has been proven as a solid platform, there will still be community support for the 5 series. The rough timetables I've seen project completion within about 1 1/2 years, but getting through the bugs for a full overhaul will require some time more. So you can keep using Perl for at least that long without needing to learn a thing.
Overall, I don't think anyone is going to lose out during the change. There are a lot of good reasons for reimplementing the interpreter, but the language designers seem determined to keep it accessible to its current fans and new users alike.