I have a Droid Bionic and a Nexus 4 and some cheap Kyocera running ICS.
The Nexus 4 and cheap Kyocera had the latest NetFlix version with Chromecast capability, yet the Droid Bionic did not.
After reading this from another user, I thought of a simple workaround for this.
Seems Netflix pushes out an older version of Netflix for some reason to certain devices without Chromecast, even though they are capable of using it.
To fix this simply edit two lines in build prop.
1.) Download Build.Prop editor from Google Play
2.) Give it root permissions if asked.
3.) Open the app and swipe from the left and click on "create backup:" This is just in case you mess it up, you can restore it later or if Netflix pushes out an update that fixes your device.
4.) Either scroll around until you find these two entries, or simply use the search button in the app.
So for sake of simplicity, I changed
ro.product.model to Nexus S
ro.product.manufacturer to samsung
Tap save on both entries and reboot! That's it!
If for any reason this causes any issues with your other apps, simply restore the build.prop you backed up earlier in build prop editor, and reboot. That's it!