Definitely agree with Steve. If I don't have to uprade my cordova version, I won't. I have had to go in a couple times and modify my viewcontroller and appdelegate files for a couple of critical issues due to iOS version updates (i.e. back with iOS 5 - the whole web database debacle - had to switch to the native sqlite plugin. also with iOS 7, the keyboard shrinking the view - had to correct that.)
I was on the cusp of upgrading to cordova 3.0, but found that I can get by with the version I'm runnning. There wasn't a big enough "improvement" to my app to use the 3.0. In the end, the customer downloading the app doesn't care if you are running the latest cordova/phonegap - they just want and an app that works how it should and looks pretty.
You asked Steve if he is worried about platform upgrade - yes, but so far, I've just been able to patch my cordova version without upgrading.