Betty has missed the point.
It's the sheer volume of time dedicated to each person's background stories that results in people getting fed up with them and so they end up feeling like sob stories deliberately pushed on us.
Things started to change a little last series. For instance Alfie was somewhere on a little row boat talking about his mum. Then we cut to a distance shot of him on the boat which must have been filmed afterwards. So that must have been set up by the crew to emphasise his loneliness. I remember it because it struck me as the first time something like that was very obviously set up.
So it didn't surprise me to learn that the main producer had changed. He's stated that the stories are what he thinks are important, and I think that's why this series the time spent on them ramped up.
The actual race elements have reduced so much that parts feel like they've been missed, and all through the threads we're asking what happened because there are now visible jumps.
Background stories wouldn't end up feeling like sob stories if we went back to the ratio of stories:race we had in the past.