Alright, I've found the answer to the issue.

Background: As I'll be going to Australia for three months of cycling, I've decided to use the Maemo Mapper as my map and GPS. Upon use Mapper to plot my route, I was faced with the same question...how do I remove a route point from a route?

The answer: It's not a Mapper solution, but here's what I do now. I go to MapMyRide.com, plot my route using their VERY user friendly and flexible web-based route plotting interface. Then when finished, export (Route -> Save to GPX, from the option bar). Save this file to the N810 and load it to Mapper.