I'd love the ability to (modify)-click an NPC and have it pass the waypoint to TomTom. Not super useful in instances, but for all those world NPCs, it'd be great!

We are actively adding coordinates to various objects and have discussed what could be done in the future. Something like this could possibly be done (and I not-so-secretly hope it happens!) but will ultimately be decided by Crieve when we have more content that would support that effort.

This has been implemented by Crieve as of commit 08ab918. You can right-click on a group header and it will apply all known coordinates as TomTom waypoints. This works at all levels of AllTheThings, including continent level waypoints. Do note that coordinates are still fairly new to the AddOn, so a lot of content will not be compatible with this feature yet.

This is now available in release version 1.7.5.