Not rooting is like keeping your money under your mattress. It's safe but you are getting no interest. Wait for your updates from Samsung. Yawn, boring, huh?
Sammy probably won't release 4.2 till around the middle of this year. Non nexus phones (I mean the high-range ones here) generally run at least one update behind the nexus line. Sammy is actually pretty quick with updates for their flagships, be glad the s3 wasn't made by moto..