see you know nothing of diplomacy. you think madara LEADER OF PEOPLEs action wont affect someones opinion of the people he leads? he didn't even attempt diplomacy he instead decided to try to use force and that's why its his fault.
I know plenty about Diplomacy, but it seems you don't know anything about the current topic. The Uchiha Clan had an option, stay in the village or leave with Madara. They chose the former. They showed that they did not agree with him and were choosing to no longer be associated with him. End of him being their 'Leader'.
Madara MADE a Village with the Senju.
Madara LIVED with the Senju.
Madara accepted Hashirama as Hokage.
What he didn't accpet was what he foresaw of what would happen to his clan if the Village continued down the path it was going.
You said he should of stayed and formed a plan, a Coup, basically.
So basically, he should have started another senseless war with the Senju leading to more unnecessary deaths and destruction.... A guy who fought and promised them Peace...... leading them to another war............
Sounds smart...........