While you shouldn't expect anything big from Android 4.0.2, the next update should bring some bigger changes. Android 4.0.3 was declared the baseline build of Android during the middle of last month. It will bring improvements to graphics, spell-checking, database handling, and Bluetooth. No word when we will see that update coming.
So for now, it is Android 4.0.2 for the GSM version of the Samsung GALAXY Nexus, which matches the build that has been on the CDMA, Verizon version of the phone even before the model was launched.