Start with an open system (but limited to notability)
& let it evolve
-- some "soft deletes" should probably go through AfD, just like some
merge & redirects should, while others could be done immediately after
the article appears.
I predict lots of edit wars as the people "deleting" the article will
have no authority. Reposting deleted material without a good reason at
the moment is clearly wrong, as it was deleted by an admin (who are
considered trustworthy). If it can be deleted by anyone (including
people who have no reason beyond AGF to be considered trustworthy), it
will be like any other edit - ie. anyone can revert it (upto 3RR).
With reposting at the moment, the default is to assume the admin was
right, and that works quite well. With this idea, the default being to
assume the random person that decided to soft delete it is right seems
unfounded.
To summarise: If anyone can delete, we can't justifiably stop anyone
from undeleting.
Counter argument: This is similar to the "PROD will never work because
the article creator will always remove the PROD tag" argument, which
has proven to be wrong, so perhaps this argument will also prove to be
wrong and people will respect the soft deletions. I'm not sure the
benefit over speedy deletions is significant, though...