If they had thought it through before, they should've called Star Trek V "The Undiscovered Country" and VI "The Final Frontier." That might've had a better ring to it and would've looked more appropriate. With ST V, the centre of the universe where they travelled could easily have been the Undiscovered Country (instead of referring to the future, or death in its original Shakespearean context). Incidentally, weren't they going to call Star Trek II The Undiscovered Country at one point?
With ST VI, not only was it the last original cast film, but also it could've been seen as the last barrier to come down between humans and klingons, so The Final Frontier would've been fitting.
