Need pre-fetch off line mode
Lots of people want something that works off-line!
I recently was in the mountains missed a turn and got the dreaded "can't connect to routing server" message. Thank goodness for paper maps.
I would suggest that if you KNOW you are going into no-data land, you should be able to pre-fetch enough maps around you to get out of trouble. This would be an OPTION as it would need to use a lot of storage for the duration and would be slower not as comprehensive but would -work-