Well every one that uses our GMRS repeater does use their actual GMRS call sign. They will use designators such as WRYZXXX Base, or WRYZXXX Unit 2, etc. And that has worked just fine for us.
I would not want to try and remember a bunch of numbers either. And you still have to use your call signs when using open repeaters anyway. Now if the repeater is closed and ONLY used by immediate family then that's a different story.