Besides lack of time, I think there is one thing which caused the IronAHK project to get frozen.
AHK in its very nature is focusing on Windows, and not everything is easily ported nor do all Commands and Function really make sense on other OSs. Especially the different Desktop environments for the X Window System on Linux are pretty nasty to support. This affects the window manipulation and also the keyboard hooks.
Some things are just not possible, or just with deep native inter ops.
Frankly, the project requires some very fundamental research for the very AHK core features. All the advanced "programming" stuff is not as problematic.
To solve this problem, deep knowledge of all targeted operating systems is required to get a solid abstraction layer for IA. However, there are some limitations which probably never can be handled.