Lol, your not going to give up, are you? Don't take this as a flame or offense, i just find it funny how driven you are
I love Woltlab and often admire where the development is going.
But sometimes they do fall short and miss the ball. I don't know if its simply because they don't want to code something (less work) or they truly believe it's not important (short sighted).
But other development either have sitemaps, are adding them, or in one case re-adding them after previously taking them out... And that is happening for a reason.
This is one of those no brainers. It's completely obvious.
1) You have both Google and Bing who offer this as an advantage for them and you
2) There is a consumer demand for it (maining because of #1).
Why alienate yourself and avoid it?