I think 10% speed gain is seriously faster. And I started with the fact that there indeed still is a long way to go.
When I started in October 2014 with CSV parsing in perl6, my first working copy took a whopping 256 seconds. From there to 3.5 is quite a thing and makes me hope it will eventually go down to 0.35, which is comparable to pure-perl implementations of CSV parsers.
The fastest perl5 parser has no options whatsoever. No options means less if statements and more efficient loops. The perl6 parser has all the options Text::CSV_XS supports, and thus includes all the code paths, if statements and other constructs to support those features. If perl6 will be able to optimize next and last to end a loop other that through an exception, I expect this process to see a speed-up by factors instead of by percentages.
I understand your stance towards perl6 not being ready for serious production when looking at speed, but if you also look at what the language offers, you might conclude that once you master the basic constructs, development-time in perl6 weighs up to solving problems in other languages. Writing scripts for complex tasks that do not depend on speed, but require serious thought in other languages, just write themselves in perl6. To me at least, it brought new insights in how I could be able to solve problems.
Enjoy, Have FUN! H.Merijn