I'm not actually on the OmniFocus team, so I don't have info on when tags may make an appearance in the app. When they do, I'll re-evaluate my workflow, of course, but I can't think of any shortcomings in my current system that tagging would address. Other folks may have different needs, of course.
Anyway, in case it helps someone between now and whenever tags appear, here's my substitute-for-tagging system:
I have a parent "People" context, with a bunch of child contexts for the various people I interact with frequently. I also have a few communication-specific ones for email and phone.
If the person is the critical element and I don't care how I get the information, the task gets assigned to the person's context. I check it when I see them, or I bring up the parent "people" context and scan the list of available actions when I'm plowing through my email or phone calls. The bulk of my people-actions go here.
If I can only accomplish a task using a particular communication method - I need to call some business I don't want a context for, as an example - it gets assigned to the "phone" context. Far fewer actions go into these contexts than the ones I mentioned before - a dozen a month at most.
If you need even more fine-grained control, add the search tool in the toolbar to the mix to slice and dice your actions even further. Assign the context to the person, but use a specific verb when that matters. Filter on "call" and you have your phone list, etc.
Hope this helps! We're extremely busy these days (go Apple announcements) but if folks ask questions here I'll try to make it back around to the thread. You can also email the
support ninjas; if they can't answer the question they can tackle me in the hall and pin me down until I do. ;-)