Give all new corridor pieces a closed floor version
Sometimes a corridor piece may straddle a non air-tight block, in these cases it would be nice to have closed floor versions of these blocks (also good for making bridges). I bought the DLC mostly to support continued development, adding floors as well as some inventory access, corridor with light and vent corridor pieces would be good value.
Maybe a medbay/survival and-or Programmable block T piece would be cool as well.
The straight, T and Cross pieces (in floored and non floored version) should probably be accessible to everyone regardless of DLC.