1- In the past, many of my models were ADAPTED FROM CAD PLANS AND ELEVATION PRINTOUTS. Elevation dimensions were often expressed in engineering units (eg. 1.63') and plans in architectural units (eg. 3' 4 1/2"). In SU this often meant toggle units which is a hassle.
2- Sections also denoted true elevation values. Being able to input a base elevation for the model (say for the top of the foundation slab) would be useful for the wall tool because the user could input the absolute elevation value for the top of a wall. beam. post. channel, etc.
I am not sure if converting existing hand drawn or digital plans and elevation is or would be a common task for users of SpecPlus (particularly in commercial construction or renovation) but, if so, then perhaps some tweaks to accommodate items 1 and 2 could be considered.