Joffrey and Marge's wedding, I am telling ya!
Last year my idea was that they could have a double first episode and have the wedding happen in the second hour, starting the season with a bang.
First, this ties the end of season 3, as they spent much screen time last year to build up to the wedding.
Having the characters gather up in King's Landing for it seems like a very logical way to handle re-introduction of all the KL players in an audience-friendly fashion since the preparations/reunions/arrivals is a set up that lends itself naturally to scenes which are more about recap and exposition than plot, and that setting will also simplify introductions of the new players (providing notably many opportunities for characters to mention them/talk of them etc.). But once that took place, they will have to move on to the wedding itself, no wait many episodes until it happens.
My suspicion at this point is that the Danny, Jon, Arya etc. story arcs will be just re introduced with "prologue" type scenes in the first two episodes (if at all for Jon and Danny), and once the wedding and Tyrion's arrest are out of the way, they'll focus episode 3 on Danny, and episode 4 on Jon, then episode 5 will again take the focus to KL, with Tommen as King.
