The original nests had the solid backs that you requested. The problem with them is that in sub-freezing temps condensation would form and freeze on the inside of the nest.
The solid mesh is better all round than the solid back was. Ventilation or a stove are the most effective ways to deal with condensation, though liners help a lot in the bigger shelters.
Does the half nest used in the Cimarron cut down on condensation issues?
I found that if I use the nest and allow the cimarron to have about 1/2 inch of air gap from ground to canopy on 1-2 sides, I have very little issues with condensation for me + 1.