We have frequently bowed down to the brilliance of the editors in this series - last week's trilogy of episodes was particularly compelling, they did such a great job (which is why last night felt a little flat maybe).
However, they can only work with the material they have, and in a semi-scripted reality show such as this, there will always be an element of things not quite working out to plan (as in the much anticipated Ross/Diane redemption we all hoped for this week that ended up being a damp squib).
It played out well for the popularity and noise around the show as a whole though, because Diane and Ross have taken on a life of their own outside of the game - which, with all the planning in the world, is sometimes not a given.
There's a balance between controlling the narrative and letting the game play out as it does when you have 'real' people involved.
I didn't see the last series, but I gather from the chat on here that the couple/relationship in that was also a bit of a non-starter. It makes me think they will work harder next year to really firm up those connections if they are to continue the idea of related pairs (which I really like - or at least, secrets within secrets...)