Basically needs more mass, which is thrown away. Not good for mission margins: "you can't have that mossbauer spectrometer because we need to put more lead shot in the heatshield so it will dig a deeper hole.

(If you talk nicely to Gary, he will tell of instances when mass reduction was so efficient, they DID have to reload heatshields with lead to balance the craft on atmospheric entry!)

And, Gary pointed out somewhere else, the heatshield engineers would be interested in visiting that location to look at the (presumably) smashed pieces of the heatshield and see if their design worked OK. how much margin was there? could they do it slimmer next time, etc.

It will take extra road mileage, since we'll need to approach the crater rim from another angle. (I suspect that going round the rim will be rougher than coming in and out by a chosen route.)

I see less value in visiting the backshell/parachute. They're off in the wrong direction anyway and have less to tell (unless the parachute tore mildly, but not fatally, but I have no reason to suppose so, and the descent modelling should show if the 'chute was working to spec.)