Actually, that's part of the issue. Most of Parrot's semantics are exactly those of Perl 6 (right down to the opcodes for Boolean testing), and those don't get along well with most languages.
The fact that Rakudo on the JVM can take advantage of the JIT to optimize simple math in tight loops fails to impress me, but I suppose it's one more half-implemented feature you can tick off the back of the box, so hooray.
