I've never heard that said about wikis before and I would rather assert wikis are where information goes to thrive. Whatever, the documentation is dead where it is, or as good as.
What needs to be released early and often is the documentation as well as the code. The docs would be best pre-released - before the code - in my view. Are the Spark team tasked by the Spark management (I know there is considerable overlap) to really be developing blue sky, do what you want, do what you think is cool, tell us about it afterwards? No, surely not. I can't believe it would not be helpful to the Spark Team to have to work against user documentation as a spec. I am not saying this might not be modified during development, just that it ought to exist ideally before devt starts or be among the first things written, first version, before any variables are declared.
How it all works is only in the heads of a few. There will always be a few inaccuracies and even perhaps inadequacies in the docs, but the Spark Core currently, and as excellent as it is, is unnecessarily difficult to develop for because the language and library docs are inadequate. Too inadequate.
So true! If all the advice so helpfully given out here, much of it patiently repeated again and again, but through over-eagerness and misunderstanding this help is occasionally inaccurate or sometimes not as full as it might be, if it were all in a wiki, then a pointer to the appropriate wiki page could be given rather than having to trot out the same old advice much of which is necessary advice for new and old here. Necessary because the documentation needs improving.
Imagine if the advice give here could just be pasted into an existing or new wiki page, or that better advice here could be used to update a wiki page. And that anyone (with a login) could do so.