I tend to agree. For me, if a runner is somewhere between first and second, but let's say not directly between the bases...maybe 5 feet towards the outfield, he has two real choices. At time of tag attempt his basepath is between him and second base. If he were to retreat, then his basepath should be between him and first base. (as opposed to an infinite line)...so if he moves three feet backwards, he is deviating three feet from his path to first base (IMO).
Between first and home is similar, and easier to administer I think, as he's typically going to be on or close to the line anyway...his path is either to first, or to home, so he's really not going to deviate if he goes straight back to the plate. And it doesn't really matter...the defense simply needs to touch first base. This would be no different on a b/r that overruns first base, but misses it...he can run to the warning track for all I care because F3 just needs to touch first base.
As far as when he misses home plate, and is between the plate and the dugout...I'd take a different tact, and not worry about basepath if he's not moving to the plate. If he retreats to the dugout he's abandoned running the bases, not much different than the batter leaving the dirt around the plate on a U3K.