Steven D'Aprano writes:
If anything, this syntax could be rejected as being too limited and not useful enough,
+1 on that sentiment.
I'm willing to bet that all of these cases are optimizations in any case. Otherwise you'd be using "class". People expect optimized code to be somewhat uglier than the textbook "teach the idiom" version. Case in point: the partition exchange sort (more commonly called "quicksort"). It's actually very easy to understand, it's just the optimization of in-place sort (well, OK, C don't help) that makes it look hard. Don't believe me? Check it out!
I don't have anything against nice syntax for optimized code, but I don't consider your syntax an improvement over the status quo. Not that it's outright ugly, just not an improvement.
Footnotes:  The start parm is if you're in a hurry. The whole keynote is highly recommended!