Warburton has clearly identified the defensive issue and has tried to ensure that both Cameron and Ball try and protect Hall and Barbet by playing a bit deeper. At times we looked like we had 4 central defenders.
I like the combo of Ball and Cameron and it works well for away games to grind out results and corrects the wrongs of recent months (Saturday being the perfect example). But as you say it is quite defence minded and we need to get the balance right because away from home we also look a bit toothless of late.