Yeah, I used to be on the No side of that argument (partially b/c history major) but the more I think about it, the harder I come down on the "screw it, it probably won't hurt" side. Going back in time and killing kid Hitler, no. You can't kill someone based on how you think they'll turn out. But later? Eh. Worth a shot.

(you could totally try going back in time, kidnapping kid!Hitler, and raising him to respect others, though)

I haven't seen the last couple seasons but I'm going to at least try the first ep of this season this weekend, because I am a sucker for time travel and it's the next best thing to getting another season of Peggy Carter hitting people with a stapler.