For over 5 years Curiosity has been successfully searching for many signs that water was once present at Gale crater. Its geology is notable for containing both clays and sulfate minerals that may preserve signs of past life. An unusual feature of Gale is an enormous mound of "sedimentary debris" around its central peak that is composed of layered material This mound may have been laid down over a period of 2 billion years, billions of years ago and is of particulary interest.
But now that the surroundihgs of the peak have been investigated for so much longer than was expected before, isn't it time to look for signs of past life elsewhere ?
At the image below, with the landing site of Curiosity we can see there has been substantial waterflow from the rim of the crater through the Peace Vallis outflow channel into the plain. An alluvial fan is drawn at the image that could be much "younger" than the "debris" that is already been so thoroughly investigated.
Opportunity is allowed to explore "Perseverance Valley" on the west rim of Endeavour Crater!
So, why not turn the wheels and head for Peace Vallis?