You're implying that AngularJS's API is Vietnam? I get that the DI system is complicated, but in my mind, it's a very well thought out approach which relies minimally on global objects. I'd take Angular's approach over jQuery's any day.
It might be clever but it's unintuitive and as a consequence developers (even otherwise experienced ones) who have not yet mastered AngularJS will write the kind of mess that is painful to clean up later. This is more or less true for any technology, but as a general rule the more complicated or different the concepts are, the less likely it is that people will get things right the first few times. And this gets worse as the application gets larger and / or more people get added to the team. A simpler approach with less cleverness would help.
