Yeah it would be quite a different game, since a lot of the unique characteristics of Cogmind are derived from its expansive maps and world, and the changes that can occur over time due to how both you and the global AI use that space.
Movement outside combat doesn't really take much time in Cogmind (aside from any time players spend considering which path to take), though one thing I haven't yet done is make the default move time adjustable so that you could practically instantly move to a destination. Interestingly no one's asked for it yet, though the current default is quite short already (50ms/cell). I can see a shorter time even being a slight drawback, if only because you wouldn't be able to stop yourself in time as you pass something interesting while running or autopathfinding to a destination.
In the end though I think some of Cogmind's seemingly uninteresting decisions are still meaningful, just not always immediately. For example deciding even whether or not to go down that long corridor or find another route can be dependent on build or tactics, and responding to new situations that arise while there clearly has an impact on the long term (not to mention the global time cost of every action).
Anyway, I agree it could be fun to have such a mode, actually a different game, probably. It would probably have to be combat oriented, since without as much space to play in there's not much room to fit variety like hacking and flight/maneuverability.
