Raising the concrete ... so simple, so elegant, so minimal in its negative side effects.
There would still be a need to mark out an angled fog line fore the pole itself but paving over the light pole foundation gives you extra width with no legal rangling.
I suspect that there is no more easement for a wider path. It is difficult to tell in portlandmaps.com because it does not seem to acknowledge the existance of the MUP.
The Sunset MUP is 8' wide; current standards are 12' - 10' as a minimum(MUTCD). I can't say with certainty but middle of the path lane striping may not be viable due to the designated lanes being of a substandard width. Might be something a silly as the act of designation a lane requires that it be X width setting in to motion a whole set of legal requiremnts. Besides, we can't see lane striping working on the Hawthorne, why would it be diffferent here?
Knowledge is NOT a crime.