My Idea: The Northern Vengeance and the Bloodier WOT5K
Basically in this fic Arya doesn't escape the red keep and ends up a hostage with Sansa, However she's still defiant and Joffrey (who in this fic is somehow more psychotic) ends up executing Sansa and Arya along with Ned.
This results in Robb and the rest of the northern forces skipping the twins and rushing south, ignoring the siege of Riverrun and going straight to the green fork. Tywin ends up dying and all the western hostages end up getting executed (This includes Tyrion) (It's a bit OOC for Robb so im thinking of having Roose have them executed instead, but im not sure just yet) this ends up having great consequences leading to a bloodier WOT5K.
I've figured out the majority of the Riverlands/Westerlands plotline, but im still figuring out the Renly/Stannis stuff and kinglanding. The ironborn and the rest of Westeros are a nightmare as well.
What do you all think and what ideas do you have? I'll be happy to see any suggestions.