I'm of 2 minds on this one. Beyond the demo footage (which doesn't really bother me because it is still promotional material even if it leaked early), I have a MAJOR problem with the remaining leaks. That said, my sense of curiosity is such that I will view whatever I can find. I'm not opposed to things being spoiled myself because I'm more in it for the nostalgia than the new experience.
I was frankly shocked at the amount of leaks that WhatCulture put in their recent video including a spoiler in the thumbnail itself. (I mean, they aren't my favorite source for video game news, but they are a big enough channel you'd think they'd at least be trying to protect themselves.)
That said my curiosity drove me to watch the whole video. I won't mention a single one of the spoilers they showed, but I will tell you that within the video, they clearly didn't know what they were talking about or even looking at in some of the images, and they even showed their ignorance toward things that have been addressed officially saying things like "Square really haven't addressed what they mean by episodic, will they be full games?"
Not only was the thumbnail spoiler annoying, but their attempts to decipher the spoilers were absolutely pathetic.