I thought it would never happen ... but it just did !
TI released a set of APIs to program the AM335x as a
microcontroller 
I spotted this a few days ago, really happy to be honest (and I can
use this one from Windows, no more rebooting!).
Adds great value for money to the device as it's $5 in bulk, the same
range as an 8-bit micro-controller (though the PCB will typically cost
more) and so this could save developers having to spread themselves
across several chips.
Still eagerly awaiting PRU support. Keep it coming TI.