The usual Free Software Foundation "loophole" on this issue is the "use this version of the license or later adopted version". This is more of a cop-out, and something that can cause further legal messes. It does, however, allow the chance that some time in the future a custom license could be merged with the GFDL in a much better licensing arrangement, provided the GFDL "upgrade" fixes some of the issues that most Wikinews users are complaining about with that license. Or fix the problems that may come up when the draft license is issued, from those kinds of things listed above.
We can very well provide such a versioning in the License... but since it would be a WNL versioning, we would be able to make it evolve to correct problems instead of relying on third parties like CC or the FSF.
Using a "standard" license means that the defense of using it will have been vetted in legal circles, something that the GPL is currently going through with the infamous SCO Linux case. Defending the license also gets popular and legal suport (sometimes) from the people who wrote the license. If we go it alone and write our own license, we don't get that sort of protection and instead put the authors and (if approved by the board) the Foundation board to stand alone with the license. On the other hand, if it is well written and very clear as well as reasonable, it may get adopted by other groups besides Wikinews.
Well, besides me, there already are many lawyers, law teachers and judges helping th e foundation today. They are helping and there is no reason they would not defend us.
A license is simply a kind of contract, lawyers write them everyday.
What we need is only a well-written one that would be tailored for what we do, that could help us understand the issues at stake, and that would help to chose others licenses in the end.