Even if such a scheme is brought in, you would still have the usual landlord v tenant arguments about the condition a place was left in, and what it was like at the start. Mostly subjective, with no arbiter except for the courts perhaps.
I know a few professional people that have taken photographs when they moved in and out of rented accommodation - left the place in good condition (sometimes even conscientious enough to get a professional cleaner in before they moved out) - yet still faced this bullplop from landlords. A couple pursued the landlord, but most give up - which is exactly what most landlords hope you will do, given the complexity, potential costs and inconvenience involved fighting them.
If government are serious about trying to bring people here, and sorting the accommodation crisis, they need not just a deposit protection scheme, but an arbiter too, perhaps one who also holds the photographic evidence when a person moves in - that can be compared to when they move out. I think most people writing cheques for large rents and deposits would even chip in to such a scheme - a fee of e.g. £30 for such a service would make the tenant feel more protected and the landlord more wary of trying anything on. Maybe run on similar lines to, or an extension of, homestay inspections?