I agree. A stupid reason to miss the 2011 window
It's only two contractors. For pete's sake just have Griffin pick one and move on.
If there is some real technical reason that at this stage it's too late for this mission, why not launch another MER? They put two of them together in less than 4 years. We have 5 years until this launch. There's no shortage of interesting places to explore. This time put some microbe and fossil detecting equipment on it.