As I understand it, Parrot appeared to be poorly designed.
Parts of it aren't right now, but that's for two reasons. One, the design of P6 has changed several times since 2001. Parrot always had the unenviable task of trying to provide a stable platform on which to build P6 and other languages (especially Perl 5, which was a goal for a long time) while trying to adapt to changes made to P6. Two, Rakudo developers actively opposed changes to Parrot, even those designed to improve the architecture of Parrot for Rakudo. (See Re^8: MoarVM update or #parrotsketch of 06 September 2011.)
...it will probably not go much further.
Now that all of its developers have been driven off, you're probably right.