I think it's more that Mort's homebrew alterations to the system has weird interactions. So...we're the beta test! Basically, with how he has set damage up, the most important stats are STR, END, and with how Fate works, it's better to have one combat skill that's really high than a bunch of moderate ones. So this all thematically favors a Berserker in the classic mold (hit hard and facetank!). It's actually weakening one of the strengths of the FATE system a little bit, since it's supposed to be "no matter how you're character is built, characters of similar skill levels can duke it on on a somewhat even keel." It's why it's most applicable skill vs most applicable skill. But now the damage rolls are one of Berserker's strongest attributes vs one of Saber's weakest attributes when taken with how we magnified stats for HEROIC SPIRITS, means we get things like a +6 shift from Berserker winning slightly in a single contest. FATE isn't built to handle that, since a +6 shift usually only appears if the opponents are really, really mismatched (Hero vs mook).
So while having them roll STR vs END seems
realistic, FATE is all about simulating
narrative, which I feel is more appropriate for nasu
. So to fit the FATE system better, I personally think damage should be more along the lines of other FATE rolls, where they select the most applicable stat for offense and defense, with the shift from the skill roll carrying over. So here it'd be Berserkers STR vs Saber's AGI (as she desperately moves to roll with the blow or somes uch) but modified by the shifts from the skill roll to give the attacker the advantage (to move things along). Otherwise, anyone not built properly we've accidentally dropped into mook status since they'll go down in a hit or two (due to the unstable equilibrium in FATE combat and how we've inflated the numbers).