MMk. this is my first post here on this site

. Um, This is why I don't like Uchihas. Yes, the Blase release is a kekki genkai. It is an advanced chakra nature that is a combination of 2 natures. Exactly like Haku's was (water and wind). Since Sasuke has been see to have both Fire and Lightning, i'd say that That is the combination needed for Blaze Release. But, the reason why I don't like them is because All of their power comes from their eyes. Even other kekki genkai. The way the Blaze release works is Sasuke casts Amaretsu with his Left eye, and controls the flame with his right eye. And since he has this power, he incorporated it into his Susano, who is shown to wield a flaming sword and a ball of fire which he accurately throws at targets.
EMS does not stop Uchiha's from their eyes bleeding after casting amaretsu or other MS abilities. It only stops the eyes from going blind.
Plus, I'm pretty sure that Madara does have the blaze release. This is because he has the rinnigan. Since the blaze release is dependant on having fire and lightning chakra natures, anyone with the rinnigan should be able to have all of the advanced chakra nature techniques. However, they are really not ever seen useing them for some reason. Pain only focused on his outer path jutsu, Madara focused on his susano and wood jutsus along with his sharingan. Obito only uses it for outer path jutsu. I think that they do not use other jutsu's, because they are not as good with them, and it is more efficient with their limited chakra to use something that they are experienced with.