Most of the MUP complaining I've seen on BF boils down to "omg, I had to slow down or talk to someone.". This isn't rocket science, if you see a dog on or next to the path, slow way down until you can tell whether there's a leash. This stuff is only frustrating if your intention is to ride the entire path like a time trial. I don't know of a single other type of route that will provide you with miles of intersection -free riding in an urban or suburban setting. Having to slow down or stop occasionally is a rather small price to pay for that.
Best interruption I've experienced on a mup was when I had to ride through the sprint practice of a high school track team. The coach basically just worked me into the routine and it was actually quite amusing. He jokingly offered me points for hitting a runner so they'd have incentive to run faster. Way more fun than getting close-passed by a semi.