I said in the post. The original character had so much going on inside his head, he was being betrayed by his own clan who he respected, he should still be grieving over his brother, he still had unfinished rivalry with Hashirama, he fought for Hokage role and his own people accused him of starting to restart trouble (where was this in the manga? this was pretty interesting.) We're seeing only minor facial expressions of what his emotions should be at this point.
In my head, Madara was the wise, legendary ninja that the legend made him out to be. And he really should be as well, it's just dampening his character into just another arrogant Uchiha douche. The random, seemingly out of character crazy smile at the end, the sudden 'oh and im turning evil now too because thats the reasonable response' in my opinion the Madara we have seen does not have enough motivation to turn into a raging psychopath. He has been betrayed and made second best but the logical thing to do is just respectively leave the village and say 'this place isn't for me, the Uchiha clan are pathetic backstabbers and have no honour' and just leave. Now he's going all cliche crazy psychopath sharingan look and it's just embarrassing.
That's why Kishimoto should just leave the legends as legends. He's just domesticated them and he clearly does not have the manga space/patience to expand the character well. It's a thing called ambiguity, the less said about them and the less we know the more mystical and impressive they are.
