I agree with some of what you say, but disagree strongly with some other points.
What cannot be escaped is that a man died. And, regardless of how the man's family reacted, the indictment against Stallworth wasn't brought on their behalf, it was brought by the people of the State of Florida. It is their will that must be satisfied, not the will of the family, although the family should be completely without some voice or standing.
If this is seen to be a case of Stallworth's wealth "buying" a favorable outcome, then everyone loses. And, I don't know how it could be seen as anything else. Florida's statute reads as follows...
DUI/Manslaughter: Second Degree Felony (not more than $10,000 fine and/or 15 years imprisonment).
A sentence of thirty days seems awfully anemic compared to the possible 15 years and $10K that could have been levied. I think a sentence of a year, given Mr. Stallworth's cooperation and contrition would have been more palatable.
Another point should be mentioned. The exact location on the causeway where the accident occurred is wide open eight lanes, four each way. The victim was not crossing in a crosswalk but dashing across lanes to a bus stop. Stallworth’s culpability depends on the alcohol level in his bloodstream and the probable fact that he was traveling above the speed limit. Had either one of those factors not been in play, the man’s presence in the middle of a highway arguably would have shifted the blame from the driver to the deceased.
I think Stallworth had a stronger hand in a potential trial than people generally realize, but he probably decided to take this deal in order to put the whole thing behind him.