Am I really the only person to notice that 'Let's Kill Hitler' as a title actually has nothing to do with Hitler? It's a reference to time travel. 'If you had a time machine, wouldn't you go back and kill Hitler?'
It's supposed to be representative of Mel's irresponsible character and as an excuse to get them out of present-day to somewhere dangerous and conducive to River Song's dress sense.
What I did NOT like was her attempts at being an 'action heroine'. Mel was an awful character. She was clearly not somebody who Rory and Amy would hang out with. She wasn't even a realistic character. What, am I to believe that she stole an American sports car and raced across a cornfield, before pulling a great big pistol out of her ass?
This is a tiny village in England. Nobody has a sports car, and guns are certainly not THAT easy to get your hands on. What I DID like was the Doctor arriving with the newspaper and saying, "Really?"
That was funny. That's the reason I feel complimented when people compare me to him.
Going to Nazi Germany to 'kill Hitler' was a comment on irresponsibility and why the Time Lords enforced their rule of only watching. Those time-police idiots were a symbol of that, too.
While I hated the fact that the Doctor was just so easy to kill in this episode, I suppose it shows that there's a deeper reason for his reluctance to have any kind of contact with women...though you'd think he'd have a backup plan.
I hate River Song. I just hate her character. She does not look like a badass action heroine, she looks like an old woman having a mid-life crisis. Doctor Who is not about gun-toting warriors. It never has been. It's been about the Doctor solving problems with his ingenuity and time-travelling spaceship. When you start bringing guns into it, it just doesn't work. And for a girl programmed to kill the Doctor, she does a pretty poor job of it, spending only this episode trying to kill him.
And nice dodge on the genocidal humans. In the first episode of this series, the Doctor tricked the Silence into getting the people to kill them. So kill all Silence on sight. Fortunately, the Silence is a cult, rather than a race. Except they all look the same anyway, so good luck with that.
So...yeah...in summary - the episode was not about Hitler, it was about why Time Lords had to police the time stream, because otherwise you get people going back in time to stop Hitler. River Song is a stupid character and had better not show up again. I like Rory, and I like Amy. Rory's growing more into his own character, and I think his time of being envious of the Doctor is helping him become a more blunt, straightforward version of his rival. I think since the Doctor made him rescue Amy in his centurion uniform, he's starting to see the Doctor as a partner, rather than a love rival, after his little jealous phase.