(Not all links work yet. I will fix it up when I'm not on the clock.)
Over on anyway
there's been some argument about shared character ownership, and whether it's possible to make useful thematic statements with any of these.
Let's view this problem in terms of elements of exploration
. When we talk about power in an RPG context, we're talking about the ability to introduce and change elements of exploration.
If you can use your ability to introduce and affect elements of exploration to help achieve your group's creative agenda, then you can be satisfied as a creator. If you can't, there is no way to be creatively satisfied. (You might be satisfied by other things, like the social interaction or the observation of other's creativity, but you won't be creatively satisfied.)
Is your ability to help achieve your group's creative agenda strictly grounded in the sole control over a protagonist (a subset of character)? No.
Is your ability to help achieve your group's creative agenda strictly grounded in sole control over any character at all? No.
Is your ability to help achieve your group's creative agenda strictly grounded in having any control over the character element of exploration? I'd venture another no.
Is it possible to have significant control over multiple elements of exploration and still not be able to help achieve your group's creative agenda? Yes.
I venture to say that it is impossible to make a direct 1-1 correspondence between control over elements of exploration and the ability to help achieve your group's creative agenda. If we're talking about different methods of controlling elements of exploration, whether or not some method will let you help fulfill your group's creative agenda is a total red herring
. To address that, we need to take it in the broad context of the other rules of the game.
As far as I'm concerned, this is really basic-level stuff. What's with the hew and cry?