I have seen several discussions on this subject but I don't retrieve them. Will it, when the dust settles down, be possible on MO2.0 for someone asking a question, or posting an answer, to make it community wiki ? Right now it doesn't seem to be possible, and I think it is a really bad change from the old version. (otherwise I like the new version pretty much, but this issue worries me)
When posting a question one cannot make it into a community wiki question. That will have to go through flagging your own question and requesting the moderators to do so.
Seeing how the volume of CW questions shouldn't be that large, that's probably fine.
When posting an answer, however, there is a checkbox at the bottom right part of the answer box which allows you to make it into a community wiki answer. That's still available for everyone.
It should be noted that now moderators can reverse community wiki status, for example if someone is updating their question and accidentally stepped into the amount of edits which trigger automatic CW.