Apple stopped releasing the standalone iPod updater as another means of forcing people to use iTunes. They also do everything they can to make it VERY difficult for other programs to work with their hardware (like iPods), so it's probably very hard if not impossible for MC to offer iPod updates. I can't say whether this will be possible in the future, but at the moment, the ONLY way to update an iPod is with iTunes, and there is no indication that this will change anytime soon.
The short answer to your question, therefore, is "Yes -- you need to use iTunes." That said, it doesn't seem to cause any real problems to install iTunes JUST for this purpose -- just make sure you turn off all the "automatic" stuff when you install it, such as "launch iTunes when an iPod is connected," or the "auto-scan for media files" features. Basically, go through ALL the options in iTunes and verify that everything is "disabled. If you turn all this stuff off and only launch iTunes when you need to update your iPod, it "shouldn't" be a problem -- just don't run iTunes and MC at the same time.
If you REALLY want to keep iTunes off the system, however (which I completely understand), you can go to an Apple store near you and have them update your iPod (which is free.) I used to do this, but I have since installed iTunes on ONE of my systems, which I use for iPod updates. So far, it doesn't appear to have caused any issues.
Larry