There are a couple of ways of accessing the address book, but probably neither is exactly what you are after:
-When compiling a new email, you can click on a recent, bring up the option to edit the Contact.
-By choosing the Window->Address Panel menu item, it brings up a list of Contacts in your address book...but doesn't seem to allow editing.
But the question is this: how frequently do you need to edit Contacts? On a newly installed/migrated system, this will be a requirement for the first few days, after which things should settle down.
I too am a recent switcher and I decided to give Outlook a miss, initially because of the premium MS puts on it and then also because I prefer the separate approach OSX takes. Mail, Calendar, Contacts, Tasks & Notes all in one app makes for a very cluttered environment.
Give it some time, I think you'll grow to like the modular approach.