Do you really know what you're talking about?
It appears you don't.
In what way is a heterogenous system related to typical amiga hardware or typical desktop processor? A scheduler does not magically split up tasks into threads and spread them amongst the cores.
Who mentioned threads? The scheduler decides which TASKS run on which cores and moves them around when needed based on CPU load.
Software has to be written to do so (no matter if asymmetric or not).
That would be multi-threading. Do keep up.
The lack of backward compatibillity is another point. Software written for existing and available linux drivers/hardware/smp won't run on bare aros.
Yes they will, it's just slow.
This slows down developement on native aros, if it not kills.
You keep mentioning AROS when were are discussing ARIX. Please pay attention.