Kishi probably screwed up... he's been inconsistent with Sasuke's Eternal Mangekyou, too. Sometimes they eyes are symmetrical, sometimes the inner design points in the opposite direction on each eye. I guess it's possible Sasuke can activate different stages of Mangekyou, but it doesn't really make sense.
Who could have guessed that Uchihas are genetically inclined to be emo.. I like it. Makes sense, especially in Obito's route to evil.
I guess that's the danger of having overly-charged Spiritual Energies... they react too heavily to one's mental state, especially considering the mental energies are already channeled through the eyes.
Are we to understand that Uchiha emotions are naturally more intense, and thus harder to handle on an objective, rational level? And what does Tobirama mean when he states that the Uchiha "sealed their love off" themselves for that reason? Does he mean they became a clan with strict standards for self-control / emotional repression? Or is it something in the Uchiha's mind that literally needs to be unlocked?
I feel like this development pushes the Uchiha characters too far down the path of symbolism.... they were already representative of intense love that can easily turn to intense hatred or anguish, but this genetic explanation (even if it ties in with what we already knew about unlocking the Mangekyou) is just too much. Not only that, Tobirama makes it sound like he's seen quite a few Uchiha unlock their MS, when until now it seemed like a rare phenomenon.
Frankly I don't see a better possibility or "excuse" as to why they as a clan are so emotionally unstable. I prefer the word exaggerated or caricature to describe the situation.
This could be why Obito was picked..if he was picked. I wonder since Obito was an unstrict person, when he activated his mangenkou is that why he basically went over the edge and had a dramatic shift in persona. Because obviously he couldn't be the only "goofy" uchiha.
Just out of curiosity, what happened to that extra Zetsu that was pulled out of Sasuke? Four of them went to the Edo Tensei, one was for the Orochimaru switcheroo, but did that last Zetsu get killed or something? Even so, could it still be used for a final summoning?
Well, if you think about it, Tobirama having seen a few Uchiha unlock their Mangekyo Sharingan wouldn't be too strange. Their time period was full of war, which naturally places a huge emotional strain on people. If there was a time that would be guaranteed to unlock the Uchiha clan's visual prowess, it'd be that. As for the Uchiha clan "sealing" part of themselves away, I think that was more a figurative way of speaking as opposed to literally sealing something away. You ever heard the saying "Still waters run deep"? It means that often times if a person acts calm and reserved, they actually have a deep emotional ocean underneath the surface. And family members can often share the same mental/emotional traits. But often times with people like this, you don't actually see their emotions run rampant until some sort of tragedy occurs, and one of the usual responses to tragedy is anger.
I could go on to say, anger leads to hate, etc., but I don't like crossing genres.
Anyways, we've seen this response in Sasuke throughout the entire manga. He acts cool and rational, then something happens which provokes and reveals his emotions, and it pushes his powers up a level. The same thing happened with Obito. And from what we've seen, it happened to Madara as well. Now we've gotten confirmation that it's a family trait, so in a way, it makes Sasuke less special than before, since this sort of powering up could potentially happen to any Uchiha in the right set of circumstances.