Nicely phrased question!
I actually moved away from making a persona into a real human. The teams I’ve worked with have found it easier to use the behavioral audience segment narrative style because it’s based on a foundation of cognitive empathy. Sure, you can use this same foundation and create a human character, but what I’m trying to aim for is more of an archetype. When using the archetype, you talk about the range of participant demographics. But you focus on the common patterns of thinking that you can support, and thereby make different support for one archetype than for another. (There’s no reason you can’t have many front ends to one back end, and I think this is the direction that software has to take to get out of it’s awkward teen years. ;)
(I also mentioned some similar things in answer to Jeff’s comment.)