Boldness is in the eye of the beholder, but the most provocative choice both McCain and Obama could make is not to choose at all–to revert to the time when convention delegates were free to argue and advocate for the candidates they wanted.
Both McCain and Obama have disaffected members of their own parties to win over, the most conservative Republicans and disappointed Clinton Democrats. Their choices are sure to lead to unhappiness among factions of their supporters.
If the delegates did the choosing, both the candidates and the country would get answers to important questions: Do Republicans value the Religious Right over moderation that might attract more Independents? Are Clinton holdouts more important to the Democrats than the possibility of reaching toward their center?
An open contest would enliven both conventions and keep VP vetters very busy.