Anyone who has used Rapscallion will know what i mean. A way to set up 'journeys' ie the steps between two locations (inlcluding special commands) and then the software being able to extrapolate and join journeys together to make the shortest route between any two known locations. ie if you key in the journeys from A-B, B-C, C-D and D-E, the software can compute its own (best) route from A-E etc.
I guess this may be a major piece of programming but for me it is Rapscallion's most redeeming feature.

also called speedwalks.

Absolutely on the journey. That is one of the main reasons I still use Classic. I would be tickled pink if one of the osx Mud clients would add a journey feature. The first one todo so in my opinion will grab a huge following right away.