This is an excellent thread (so far). At the heart of the issue (and this is something that has been discussed in other threads, too,) is the idea of differences between a creative genius and a technical genius. The basic question is which is better? I think the answer can only be subjective. However, more and more I see assumptions that the technical trumps the creative.
In a book about bassists which I read recently, the author says something to the effect that McCartney wasn't the most technical bass player in the world, but he was the most famous. He then goes on (in my opinion) to make statements which make me think he prefers the technical over the creative. If I had to choose, I'd take the creative over the technical. When I listen to bass playing, I'd prefer something that sounds great and makes the song great, rather than something which is more of a display of technical virtuosity. I suppose each has its place. And this isn't taking into account that sometimes the creative and technical exist at the same time. Personally, I'd say Paul McCartney himself falls into that category, even if he doesn't usually try to play a million notes a minute. What I see as a problem is the assumption that someone such as Paul McCartney couldn't be way more technical if he really wanted to be. I'm not saying every bassist who is creatively brilliant could also be technically brilliant. But I think many can, and this certainly includes Paul. I think he could have done just about anything he really wanted to, especially if he had concentrated on the bass to the exclusion of almost everything else. In other words, if had only played bass, and had not sung and composed songs, too.