I don't see any way they can get rid of the "biting" of newcomers without overhauling their policy. Mainly, the problem is that Wikipedia deletes a lot of useful content because it doesn't fall within their idea of what Wikipedia is supposed to be about. No matter how nice, polite and civil they are about notifying people that their useful content just got put up for deletion (or has already been deleted), it's not going to make those new editors very happy.
Yeah, there are a lot of other wikis out there where people can post their content. But those wikis aren't sufficiently integrated with Wikipedia to take advantage of the economies of scale that Wikipedia offers; therefore, those other wikis tend to fail. The WMF has not placed a high priority on interwiki integration, even among WMF wikis; there are no integrated watchlists, interwiki page existence detection, etc. That's probably a large part of the reason why those other projects haven't succeeded to anywhere near the extent that Wikipedia has. It's easy to complain about such problems, but I also intend to address them by coding some solutions.