In my opinion, neither option is acceptable, and the second one... the existing rule is much more accurate and appealing (you can include Berserk and Hypnosis, for example). And, first of all, because the rule being discussed regulates the use of
only magic as such.
After all, there are quite a few related factors.
* If you cast a spell, but the opponent resists it, or you don't kill anyone at all (you take 30 hit points from a wyvern, for example), can you run away?
* If you cast a spell, but it's reflected back on you and kills your own units, can you run away?
* If an attacker on a Dragonfly kills three of the opponent's goblins out of 500 with an arrow in the first round and runs away, is that a Hit & Run?
* If an attacker with a hundred dogs (like in the Roland vs. Samurai battle) – Crag with high attack and expert attack, or Orrin with expert shooting and a golden bow – manages to attack the opponent, causing significant damage, and escapes without taking much damage himself, and all without using magic, is that not a Hit & Run?
And when a Gorgon attacks/counterattacks with additional damage from her ability and kills an additional dragon, archangel, etc...
The concept of
Hit & Run is much broader and even has a right to exist as a complete non-restriction. ;)
But since restrictions are being introduced, why not take into account the hit points of the units involved – before and after the battle? So that the facts are clear and specific. Let's say, hypothetically, that if the attacker on a Dragonfly deals more than 5 times the damage (more than 100 points) to the opponent with any of his magic, then he cannot escape in the first (second, third...) round.
Although, you could also leave everything as it is and not change anything.