As Arno pointed out, there seems to be no big issue to use SL as blackboard for DGS tournaments.
Yet following could be considered: rather than create new pages for each tournament year, why not stick to a page 'DragonTourney?' with subpages (exxample:)
But here is an idea: why not use SL's page history mechanism to store past tournament results?
So in the current page, a visitor will find links to past versions of pages, containing results, rules, discussions, etc... that were applicable then.
And when the big history hoover cleans (rather prunes) page history, well... tough luck. But nobody will weep for that in the future, I'd say.
Another question: is it really necessary to keep a record of past tournament results on SL? Who cares about what player X did in 2005? That player Y won the 2007 tournament? Aso, DGS users come and go, resulst don't have the same value as the Castle Games...
Also: avoid questions and discussions on pages, use the discussion pages for that.
The overall guideline should remain to try to leave as few garbage behind as possible, and reduce the pressure on the SL search engine (so that it can return significant results).