Lego now uses the back of the box to highlight all of the play features of the set. Compared to the sets of just five years ago, the new sets seem to have far more play features. By all appearances the new features help sell the sets which is why they get the back of the box treatment (it is all about selling sets after all).
On a similar note, many of the new sets use far more Technic and specialized pieces. These don't lend themselves to as many alternatives, so there may not be as much to show using just the pieces in the set.
Some kids and parents may get frustrated by the alternative models shown on the box as well. While the old pictures do inspire creativity, the alternatives can be hard to actually replicate without instructions and are often very fragile as well.
In recent years, Lego has posted alternate designs online with instructions--not a bad idea.
"He is a very shallow critic who cannot see an eternal rebel in the heart of a conservative." - G.K. Chesterton