AHK has the distinction of being an absolutely indispensible tool and a horrendously terribly designed language. It's probably the worst-designed programming language I've ever seen. Whenever I'm frustarted with how slow and conservative Python development is, I remind myself that this is the main thing keeping us from reaching the same state as AHK.
I hope that this upgrade will fix some of these problems. I'll probably take a few years before I upgrade my AHK scripts.