What NASA desparately needs to satisfy its Mars constituents - folks like Eby and Cowing - is to have a least 1 rover working on the surface of Mars shortly.
To insure this NASA intends to launch 2 rovers simultaneously, instead of testing the rover design and command and control structure by launching 1 rover first and then following it with a second.

Pathfinder showed the incredible bandwidth and resources needed for full remote operation of rovers on Mars - the question is whether the relay system and whatever degree of autonomy they have built into these rovers satisfies those requirements. (I have no idea what degree of autonomy these rovers have been equipped with.)

Due to these decisions the results may end up being one of the following:

1) both rovers fail due to a shared mechanical design fault, or simply due to the vagaries of chance

2) one or the other of these rovers succeed

or

3) both succeed mechanically, only to be used in a less than optimal manner because of the command and control restraints presented by the limited resources available ot support their operation on the surface of Mars

ep