Interesting Dispel Magic Questions

[schm0]

The alternative would be to work out a heuristic to apply, an easy test, to determine which of the four sub-specializations of the Range of Self, applies to a particular effect.

For the vast majority of spells that have been examined, we don't need a heuristic. For most spells, their effects are apparent, and thus the question of "what to cast it on" never comes into play. Other spells have me wondering when, if ever, they might become dispelled (i.e. commune, for example, is unlikely to ever be cast in front of hostile parties.)

As I have pointed out many times, the only time such a conundrum might occur is if the spell effects are imperceptible, the spell can't be identified using an reaction, and the party/NPC doesn't have access to detect magic. Such scenarios are quite rare, in my experience.

Uh, what? It bestows on the caster a 15' radius aura that damages things and slows them down. I find your take to be well off the mark.

It does not "bestow an aura". It creates "spirits" that "flit around" the caster. This magical effect does not reside on the caster at all.