Alright as the American who better to comment.
1) Americans are use to seeing the English in the roles of American Superheroes. Does anyone remember the new Spiderman or say Professor X from the X-men movies? So for me that is a non issue.
2) Superman may be from Krypton but he grew up as an all American farm boy from the mid-west. Those ideals are what began and molded him. However, (yeah I caught that 80s reference and have to use it) the 80s comic Superman did some departure from what had come before. There the writers took him on a world tour before he was introduced to the world allowing him to see how different cultures approached things. Knowing he could easily be a god if he wanted it was that farm boy upbringing that kept him in check. At heart he is Clark Kent not Kal-el.
3) This is supposed to be the first of the intro stories as DC prepares to copy Marvel's idea and finally give the public a Justice League movie. So we are about to get a new version of Batman, Wonder Woman, Flash, and Green Lantern within the next few years. Let us hope for the most part they don't copy the new versions that DC released, but take the images most people are use to and modernize them. (Truthfully as long as you keep the colors, cape, and shield for Superman he has had a number of alterations over the years.)
4) I haven't heard of Johnathan Kent pushing for Clark to let someone die, although even in the comic he has reminded Clark that while he might be Superman, he isn't God and can't save everyone. So without seeing the clip I can't comment.