re: As we increase the resolution of features, interests in those features and time...
will determine the need to be at the features at the start of the surface mission. These Rovers are going to be to big to use airbags of current design.
Imagine if Spirit was already at the most interesting spot from the get go...but accidental drops into the mother lode happen (Opportunity?).
The skyhook is not favored by some engineers (I believe Zubrin is among them). But skyhook is needed and offers several interesting possibilities for ISRU refueling tests and it's own hopping around mission (if they think about it). I think they should have made the MER Lander have some minor data gathering abilities (a weather station and camera to see the rover depart).