Ok the origional concept of it was to be able to read enemy movements and copy their techniques...that was cool. Giving it the ultimate genjutsu and the strongest fire jutsu that was ok if it was a one tome style use like it was at the start. Then it was ultimate defense susanoo with an unblockable shield and a sealing sword which was the line (as it still caused blindness) then EMS was added and it said all the risks to hybrid sharingan....well those risks are gone now. Now the sharingan has the three tomoe spinning ring of death. Then Madara shows up and decides he can make susanoo clones and that he can shoot several three tomoe spinning rings of death and has a perfect susanoo that destroys mountains. And there is even Izanagi to cheat death (has a fair risk) and izanami, but that's actually fair all in all......It is getting just a tad bit rediculous to be honest. The rinnegan was supossed to be the greatest of the dojutsus but it is basically tied with the sharingan if not inferior now...and so much for three great dojutsu. The Byakugan is a joke now! Maybee if it was given an ability to defend at long range it could be considered great once more. Sorry I'm not really flanking here I'm just trying to state how it developed...I thought it was perfectly fair when the sharingan's amazing power caused blindness, but now its like a get out of hard fights free card :/
