You know, leading up to the first season, I remember hearing interviews with Benioff and Weis where they talked about how much they loved the books. Benioff (i think) in particular said it was, to paraphrase, one of the greatest things he's ever read. Liar. Ignoring the asoiaf mythos and continuity is not something a fan would do. I'm not talking about changes to the plot for realistic budgetary/showbiz/scheduling/whatever demands. Hell, Im not even talking about their whitewashing of several characters (jon,arya,tyrion,robb oops just talked about it). Things like the robb-talissa septon marriage help me to realize that the creators of the asoiaf adaptation are not true fans of asoiaf.
I'm not understanding how they ignored ASOIAF mythos when Ned Stark (you know, Robb's father, Lord of Winterfell, Warden of the North) got married in Riverrun's sept. Not in front of a Weirwood, not in Riverrun's Godswood, but in a Sept. Which probably means that a septon also did the ceremony. So, they show a marriage, that we knew nothing about the ceremony, include aspects of the Seven into it, but have it in front of a big ass tree, at night, in a likely Godswood (which is similar to Ramsays marriage) and they know nothing about ASOIAF and aren't true fans of the series.
So tell me, because no one is doing this, if you created the show, how would you have portrayed Robb's wedding to Jeyne/Talisa? Now keep in mind, they are in the Westerlands where there are few Weirwoods, a few Podunk godswoods, Jeyne follows the Seven so she will probably want some of her faith included as well. I'm not sure anyone can do much better.