Help me define which features have been abandoned.

If the wiki is supposed to be serious business, I think you should scrap it and start over with one that places all submitted content under a non-restrictive license like CC-0 or MIT. As it is now, under the wiki license, you're not actually legally allowed to use any of the code there.

 

Mecanim is still rough. I am trying to use StateMachineBehaviours but there are so many ways they are not triggered or are triggered in ways you wouldn't expect. You have to use Enter/Exit nodes, but there is still no way to Crossfade to an Enter or Exit node.

They added sub state machine functionality to improve the graph flow but no direct way to check that via scripting. They are adding this whole playables API but still so much of mecanim can't be touched at runtime.

Features get added but old limitations are never resolved and old problems stay broken. It feels like it has been half out of the gate for years now.