How can I deal with unwanted system applications without rooting?
No, that is impossible -- as only root can make the system partition writable (which is required to delete a system app, which is stored there). However, using ICS (Android 4.0) or above, you can at least "freeze" them (make it "invisible and unusable") -- and, if you later decide otherwise, also unfreeze them again (see e.g. How to Remove / Disable the Bloatware Apps in the HTC One X or Bye-bye, bloatware: Disable system apps in Android Ice Cream Sandwich).