The biggest issue with most endgame sorc builds is that nearly every build revolves around infinity, which can only break select immune mobs on anything other than lightning. I built up a new fire sorc using new runewords and close to ideal gear.
Went and tried out a few areas, both using infinity and not, and lightning based builds still clear enormously faster. Many areas I can’t kill using fire at all and will have to either let merc kill, or dual element. With pure lighting, its still way faster and easier.
The only thing I can think of to balance this out would be to lower the fire resist % of monsters that are “immune to fire”.
If not, fire may be an acceptable alternative until you get infinity, but then everyone will just switch to lightning like the same old meta. Sure fire sorcs can farm specific areas, but lightning can farm almost everywhere which just makes it objectively better.