The cost of adding a feature isn't just the time it takes to code it. The cost also includes the addition of an obstacle to future expansion. The trick is to pick the features that don't fight each other.
“It is hard to imagine that, having downgraded the US, S & P will not follow suit on at least one of the other members of the dwindling club of sovereign AAAs. If this were to materialise and involve a country like France, for example, it could complicate the already fragile efforts by Europe to resc”