Some people want to just spend and receive coins without even seeing address strings or wallet details. Others will be power users, and want more fine-grained control over their wallet(s), keys, encryptions, and super-security techniques. And there's a million shades of gray in between. I don't think all this can be achieve with one client.
I think a nice future addition to the Satoshi client would be some kind of EXPERT MODE that can be turned on in the options (disabled by default) that enables all that (and possibly more).