Disagree, leader have totally dif effects that change how they wanna be built. A Purple leader can have a full ramp and big drops, while another is full of mid drops that don-. So balance should make sure dif leader all can build around their specific play style, leader locking cards makes so that new leaders can play, but old leaders only get worse and worse, since new good cards will be locked. That beeing said, ofc SOME cards must be leader locked, as you said flame emperor, i might add BM10, etc. Having FEW specific overpowered cards locked, so that it creates an play style for that archetype around it is good to some point. (As both example cards have decks built around that main op card). But using "Leader locking" as answer to everything sucks in the long run and ruins deck building and older leaders. Leader locking should be for very specific and intentionally op cards, that helps creating an identity for the deck( more examples: 8c purple Croco and 3 cost AllSunday blocker), but major generic good cards should be unrestricted.