it could explain River's behavior despite 'growing up' with Rory and Amy: Amy's hero worship stories would be all the more motivation to complete her mission if she had any inking of an unpleasant end to the relationship.

I tend to think we're supposed to read River's killing the Doctor (because she totally does/did) as conditioning rather than choice, at least going by what we've seen thus far, but I also think the Ponds are becoming less willing to follow the Doctor blindly. We'll see how things end this season.