We also make product demo videos, so we rely on Premier as well as In Design and Illustrator for other tasks.
We own several copies of CS2 and CS3, but that is the newest we have.
The Mobile Station 2 must have at least Version 1.83 for locomotives from the new World of Operation.
Current information about the new functions in Software Version 4.2 (pdf).
You would need to know what features are in use and if improvements are worth the upgrade.
Simply not having to learn a new program isn't a good reason - the company would pay for training if needed, etc.
Question Summary: What new features in CS6 and/or CC necessitate an upgrade?
What things in CS6 and/or CC make it superior to older versions (people have to upgrade for some reason besides buttons looking fancier, etc). Disregarding feature sets, that alone should be enough to make the choice to move the CS6 (I'm not a fan of the subscription model of the Creative Cloud).
Here's the big deciding factor based on the hardware you are running... You're probably aware that 64Bit means faster applications, more access to RAM, etc.