1. Thanks for posting the link; a movie like this definitely needs some exposition so that it receives a fair chance. As a result, I'm more interested enough to try and catch it in the theaters when it comes out.
2. I have a gut feeling the comparisons to Taxi Driver and The King of Comedy are going to be superficial at best, in that they'll share a similar setting. Other than that I see it as an attempt to hype DeNiro being in it.
3. One of the things about Batman that I came to appreciate only later was that at its core it's 'noir' storytelling, and so to me it seems fitting that the greatest villain in that world gets his own story in that similar yet off-kilter vein. From what little we get in the previews, this seems to have that potential. I just hope it's done right.
4. Best part for me was the video says the intention is that this is a one-off story. I think if they try to go beyond that, they'll take away too much of the greatness of the character.
ETA: 5. It's not the origin that most will want, but it's the origin that most will need.