Yaarel
🇮🇱 🇺🇦 He-Mage
A subclass is the same thing as a "feat chain".Might I suggest that if Extra Attack is going to be a feat that it needs to be a chain and the fighter needs to get something more in exchange for one of its two worthwhile class features? Or just ax the fighter and give the subclasses to the other classes?
I agree, other classes can this subclass too, as a kind of "prestige" subclass.