The thing that strikes me is the duplicate effort to implement Perl6.

In order to duplicate something, doesn't there have to be an original? Where's the existing Perl6 interpreter? In fact, isn't Perl6 itself a duplicate effort? We already have a perfectly usuable and Turing complete Perl5. Anything that you could do with Perl6, you can already do with Perl5.

Aside from being an academic exercise,

What's wrong with an academic exercise? Maybe the author is doing this mainly to learn Perl6, or Haskell, or interpreter design. Maybe producing a Perl6 interpreter is merely a side-effect of the author's goal. In that light, Pugs is pure gravy.

wouldn't it be more prudent to contribute to the existing effort or do it in a way that would be allow people to "download something and start coding" - namely in within Parrot, in c, or even in Perl 5?

What if you don't agree that the current effort is proceeding in the best way possible? Should a person merely sit around and complain, or do something? What if the author isn't interested in Parrot, or C or even Perl 5. Why should anyone have to volunteer to work with tools they don't like?

I applaud the effort, but is this really going to be useful in the long run?

What if the author isn't interested in being useful in the long run? So what if it doesn't become useful in the long run? In the long run, we're all dead. Nothing ventured, nothing gained.

If not, why create yet-another-project to draw resources away from what has already been committed to?

What resources are being drawn away? It seems like a large chunk of resources have been added to the existing effort (Pugs is the proof). Are you paying the author money which you would have donated to the existing effort? Do you wish to force the author to do your bidding? Isn't Free Software all about the freedom to take a project in any direction you see fit?