Every mission, from Shepard's ballistic flight to after the first untethered spacewalk by Mc Candless in 1984, was an improvement from the previous ones (with the exception of several failures).
From around 1984 to now (with the exception of satellite rescue flights and the first space station docking) every shuttle flight was pretty much like the previous ones.
Is the way for NASA to survive, constantly to vary the missions? (otherwise it becomes boring).
From 1961 to 1969, there was one goal: to land on the Moon and return back.
Then after that, what's next? Mars!
Yes, footprints and flag....Why not?
But then we should be consistant with this philosophy of gradually improving on our reaches.
This is done through unmanned probes and perhaps they should get a boost.
From Apollo 8 onwards, it became increasingly clear that what captivated the astronauts most, were not the wonders of the proximate world (the Moon) grey and barren beneath them, but the beauty of the far off one they had left behind.
From Archibald Mac Leish:
". . . to see the earth as it truly is, small and blue and beautiful in that eternal silence where it floats, is to see ourselves as riders on the earth together, brothers on that bright loveliness in the eternal cold-- brothers who know they are truly brothers"

The Earthrise picture also started the environmental awareness.

Raoul