You have to read Bill Kristol through a certain prism. He spent the entire primary season pining for candidates who weren't in the race. And he concedes he might be unfair to expect a game plan to be included in a convention speech.
But he's also right that Romney has mostly floated and hasn't done much stinging. President Obama's record, or lake thereof, is a target rich envrionment. To stay with the boxing metaphor, it's time for Republicans to take off the gloves. Mostly Republicans cannot let Democrats change the subject. This is the starkest contrast voters have ever had. Democrats will do what they can to divert attention from that contrast. Romney/Ryan needs to keep this campaign about the big issues that prompted Romney to pick Ryan; entitlement reform, long term debt and the economy.
And this campaign needs to be about $4.50 a gallon gas and "you didn't build that." It reminds voters of what President Obama really thinks of small business. The "sting" Kristol refers to is the sting of truth. It's what this campaign should be all about.