@highlandparker, I "kind of" already use the app that way. I often make a long trip, and think up some shortcuts in advance. At a decision point I use a shaping point, attach the cube-icon to it, and add a note to it that says something like: "If it is getting late, skip to WP 23, it saves you 40 minutes and 50km." That works pretty good. But it can always work better 😉
I think it would be nice if an alternative route could be made, and at such a decision point you could simple get a dialog "tap blue for the original route and red for the alternative, it wil save you 40 minutes and 50km."
On the other hand, it is a kind of luxury problem.