I think initially this seems odd and I certainly missed it but with the filtered views seeing a week by activity pretty much does it. What it is not is graphical and that is what is missing as the brain can absorb graphics better. I guess it really depends on the type of user you are and how busy you make your calendar.
The monthly view is too small so I am with you I think I would still prefer to have a week view.
You are right, there is no week view in the built in calendar.
But please try the app "Week View" - it has a free trial and many other features the built in calendar does not have (week view, search for appointments, replacements, configurable live tiles, ...)