Shapeshifter, thanks for the heads up.
I get something on this topic every few days or so. The reality is that the vast majority of themes (including the WP default themes through twenty-fifteen, which isn’t even out yet) use get_stylesheet_uri() and do not use the so-called “new” method at all.
Therefore the only way for a plugin to be sure to load the parent styles first and then override with the child styles without additional functions is @import.
We could add a function to the child theme functions.php that dequeues the parent and child stylesheets to get to a baseline, then enqueues the parent and child to get the correct cascade order, but that starts to smell a lot like spaghetti code to me.
I will come up with a solution in a future release that will calm the Google performance police but for now, having seen hundreds of good, bad and ugly themes come across my support desk, CTC uses the best practice for the many.