I think ratings have gone up as word has spread. Not necessarily because of the stories.
It's a balance, isn't it- you do need a little bit of backstory, as it makes it easier to relate to the contestants. But this season it was very repetitive. Far too much about the sisters' house loss and Caroline's lost sense of purpose.
And I think we lost details of journeys that previously helped make sense of the race, and added to the viewer's excitement (and knowledge of the contestants, actually).
Take episode one. Fin and Sioned couldn't work out how to get out of the starting location. Then without much explanation they were suddenly comfortably amongst the front of the pack. Compare to episode one of the Canadian season. Cathy and Trish similarly couldn't work out how to escape their starting point. The viewers were with them every step of the way, and felt invested in their journey.
I do think the balance needs adjusting back to keep the show compelling.