With the new zone blocking scheme being implemented this year, the running game has been a diappointment. But... sometimes you take a step backward to go 2 forward and this may be what we are seeing.
I think Davis is the best back. Wells is okay, but nothing special. Hollings has ton of talent, but very little experience. I still feel Davis is the best option, if he is healthy. His inablility to stay healthy is starting to be a concern.
This team is not going to master zone blocking in a handful of games. Denver has proved this system can make a average back look very good.