652 individual changes were made to the Perl 6 spec during 2009. I had amind to read through them and make some sort of list of honorable mentions; unfortunately, that's not likely to happen in the next few days.
But I might as well mention why I got a sudden urge to list noteworthy changes: it's because in 99% of the cases, I like when the spec changes. A lively discussion in the last few days contained mentions of a proposed 'freezing' of the spec, in order to 'get there sooner' with Perl 6. I don't think freezing down the spec at this point would help us get there sooner. It would be if, say, most of the spec changes were ambitious semantic additions and new features. But most spec changes nowadays are responses to questions, complaints, comments and points of particular confusion from implementors, users, newbies or random people of Twitter.
Maybe I'll get around to summarizing the spec changes of 2009 later in January. Right now I'm having too much fun coding on a Perl 5/Perl 6 hybrid application.