Pagonging has not happened on this show for many seasons. In the early seasons it happened repeatedly, until the producers found ways to encourage flipping by incorporating tribal switches, challenges that reveal the pecking order, and "buddy rewards", and through trial and error, participants figured out how to strategize flips and pull them off successfully. I don't think the lack of flipping is this time is so much a result of not including those "forced" elements or bad casting, but because Rob knows how to engineer things to his advantage, and as has been repeatedly pointed out, his current alliance would be no better served by attempting to flip at this point in the game, even if they were the smartest, most strategic bunch in the world. I think this season when they introduced the RI twist (which I personally hope they DO NOT repeat), the producers expected that to provide all the shakeups and unpredictability the game needed, and it still might (and the first time it came into play, it did provide one of the most compelling blindsides the show has ever seen), so they didn't feel it necessary to do a tribal switch as well (when was the last season they used one anyway?). And because there are no more reward challenges due to RI, there is no place to introduce some of the other elements I mentioned to promote flipping.
I find it funny that after one "predictable" episode, some people are throwing their hands up at how boring the season is. A week and a half ago, when Matt was about to come back into the game, everyone was singing a different tune. Oh well.