Sure, you could let it all ride with no secondary. Technically it wouldn't be an Oud Bruin as they are traditionally out in secondary. But, it's you beer so who cares
As for off flavors, it's possible that you could get some early on but the longer it sits, it should clean up and develop some awesomeness.
I have a sour going on 15 months that was just this. Pitched American ale yeast and a few days later tossed in a pack of Rosalare. At about a year, it was cry baby sour. At around 14 months, it's mellowed and tastes nice.