Hi Darcy,
I've worked with Zope for at least 10 years and Plone for about 5 (and
yet I converted to web2py almost on a "weekend" :), I think I know
where you coming from as far as your questions, here's the info I
think it might be of interest to you:
1. web2py does not have a workflow system in the same sense as Plone
has, you have to define your own depending on your application, this
may seem like "a lot" but web2py is such a rapid development tool that
customizing your workflow to your application it actually a *good*
thing imo.
2. The concept of "objects" in web2py is more in line with "python"
objects rather than "plone" (or zope) objects, remember that Plone and
Zope handle all this internally due to its Object Database, web2py
uses no such approach, in constrast, web2py allows you to seamless use
any database back-end of your choosing, so either you version your
"objects" via serialization or just use a SQL backend for this
purpose.
3. No such thing, in this respect web2py behaves as any other web
frameworks in which you have to implement your own methods to index
binary content.
4. Basically same as #2
5. Massimo defined this clearly.
Now, Plone/Zope makes a lot of things very easy, for instance,
authentication, folder/object traversal, acquisition (despite many
people hating it is a powerful thing) and other goodies, web2py,
however, allows for super fast prototyping and development, a very
concise and straight-forward approach and literally pure python for
the program's "logic". I am maintaining a lot of Zope 2 sites still
but all my new work is based on web2py now, and the rate of
productivity/delivery has only go up..