[openbeos] (G)UI design, round 2 (split from: Patch: Prettifying the default decorator)

There's been quite a bit of talk in the IRC channel about Haiku's UI, and further about who is likely to use Haiku. The constant call to prayer that gets bleated out about once every hour or so is "make personas", and my attempts to make something for the purposes of discussion got ignominiously shot down without a second thought. So I actually tried; unfortunately, the only person I figured would be fundamentally likely to use Haiku is the guy who's already used BeOS and liked it, but wants a BeOS which supports modern hardware. By that logic, there's no logical reason for changing anything about BeOS' UI since it'll only sour the punch with the guys who will make up Haiku's core audience.
This has to be a ridiculous conclusion, but I've been unable to think of anything better; the only beginners likely to use Haiku are those with friends or relatives who use Haiku and feel strongly enough to make others want to use it (in other words, the ones who used BeOS and liked it), while the intermediates are already happy with their OS and would feel too strongly about having to relearn to use the computer to switch and the experts are all using Linux and don't see the need to switch from their long-standing well-supported opensource OS which supports a wider range of hardware.
So I'll open this question to everyone - what IS our audience? If, as I surmise, it's those people who liked BeOS already, then we're back to square one and we ought to make the default decorator look as much like R5 as it is within our power to do so. Only if someone can provide a compelling alternative audience do we have any justified reason to make changes to the UI.

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