Thanks for your reply. But some of your responses just go back to my main gripe. I think some of this stuff could've been better explained. Sure this film is made with the mass audience in mind but it is also made with an eye towards the old fans as well. I don't think you have to sacrifice a movie that is true or respectful of canon in order to appease or appeal to new fans.
As for Marcus's explanation of Section 31 to Kirk, he might very well have thought Kirk wouldn't live too long afterwards, but how could he know who Kirk might talk to before or during his mission to the Neutral Zone? Or that Kirk is resilient enough-I mean this is the guy who took on and beat the Narada-and then what kind of boat would Marcus have been in? (I didn't have a problem with Marcus's reveal of Section 31. I was just wondering why he was so open about it, when we had seen from ENT that it was a shadowy organization. Heck, in ENT it was so shadowy they just called it a section at first. I can't recall if they actually said Section 31).
With Praxis, I actually missed it the first time I saw the film, but paid more attention due to some of the comments I read on this website. My issue there was that something major like that could've easily been worked into the dialogue. While Marcus is talking about the Klingon predations he could've said something along the lines of since Praxis was destroyed-either due to the kind of build up you described or a-ha, the Narada, the Klingons have become more desperate, been striking out, yadda, yadda, yadda, and war is inevitable if we don't send a message now or something. Or that Harrison has been helping them and he must be stopped before he helps them rebuild their military or whatever. The desperate state of the Klingons due to Praxis might also explain why they didn't show up to attack the Enterprise or the Vengeance later. Or heck Earth for all that matter since it seems that Earth is only a few hours away from the Neutral Zone now.
As for Carol Marcus, I heard there had been a deleted scene that did explain it. I think this wouldn't bother the new fans but it would leave old fans' heads scratching. I don't get why they just didn't let Ms. Eve use an American accent. Or at least throw a line in there about her studying/living in England for a period. The film did a shoddy job anyway of putting her and Kirk together so maybe a little conversation and her talking about where she came from could've helped established that relationship onscreen.
You can say they are definitely nitpicks. I still don't see them that way. I think they needlessly detracted from the story.
I agree with your view about the ethnicity/nationality of Khan.