I think that you've got something there Dutch.
I don't think that a diamond knot would work as well in this instance. The pressure exerted on a stopper knot is entirely different from what we're looking at here.
A triple fisherman's bend is the recommended knot for this app., but with the combination of the heat "whipping" and the shrink tube to provide traction, this could be exactly what you say:a quick and easy way to make a loop. Did you think this up yourself? Have you tested the load bearing ability?