It would be nice if Google map let you navigate a set route from your phone. Google map is very much linked to Google navigate which is primarily designed for use with motor vehicles. I remember fooling with it for a while but when I found RWGPS I didn't need it anymore. Google map I use though for times when I just want to navigate something unplanned.

There have been times when I've been on planned routes and found it necessary to bail out because I wasn't feeling good. If I had the option to plan a new route from the phone I'm not sure how easy that would be to do from the phone considering how small the screen is anyway. Generally speaking I figured there's two kinds of rides, the planned and the unplanned. If planned you just sit back and let the app tell you the next turn. For unplanned it's really not that hard to quickly view a map ( while stopped ) to see what your best options are. Even if you had the option to design a new route from the phone it would probably take you just as much time to do that than to just stop to look at the map periodically.

If I bail on a route I'm running on Locus Pro I can still display the planned route while riding in a different direction. This is sometimes helpful in getting to where I want to get. Then if it turns out that I'm hooking up differently with the return ( planned ) route the Locus app will pick up the route and start to navigate again if I want it to ( from the spot am at ). Cue sheet will do this too but with Cue Sheet you have to manually advance the map to just before the next turn. Not hard to do as Cue Sheet gives you an actual Cue Sheet. Keep in mind that with any app running a planned route if the app has a "off route alert", you might want to disable it if going off route.