So if LNAV, EHSI map etc do not increase SA, why do you think we have them?
If you are given a vector to fly you will still have the magenta line from the original programmed clearance displayed on the EHSI map, and the little aircraft symbol will indicate your position and progress in relation to it. Situational awareness preserved!? ATC will eventualy issue you a clearance to join the magenta line somewhere further down the line - panic over?