Hey Wrenchzzz,
I do agree with most of the things you suggested.
The thing I'm waiting for is the next engine version, which is planned to be released in april. There will be some changes to navmesh navigation and other things that will hopefully give the developers a bit more control about what will happen. I that new system doesn't work, I will write my own solution, but for now, implementing some of those behaviours would just kill the engine, because raycasts at runtime are quite expensive.
Just imagine every unit has to "shoot" a ray at their target to make sure that nothing is between the unit and it's target. I would end up having like 50 to 100 raycast (worst case 100 in one frame). However there will be changes to raycast in the next engine version, too, so that the AI can be improved.
Next update will be all about vehicles and air vehicles, but after that, the new engine version should be stable and I can start working on the AI behaviour.