I was just watching Charles Culp's presentation from SWW12 and I was surprised to see around 36:00 in how trimming back the boundaries a little bit so it reshapes the angles at the corners helps out so much. Maybe this will be an additional help sometimes, in the whole spirit of go with the flow.

I have found Freeform can be used as a hack to trim-convert a patch. My method is not perfect as I am forced to change the surface slightly (I just made an interim curve in the Freeform PropertyManager) so let's see if we can improve it!