I think it is right for flight schools to have students make all calls. You should be practiced in all of them before you can be omitting some.
I still think it's better to call for entering, downwind and base- if there's no traffic, what's the harm? If there's lots of traffic, yes there is a lot more radio talk, but when there's lots of traffic that's EXACTLY when you do need more clarification. So long as old mate isn't having a chat about his kitchen renovations when it's busy.
I also always announce clear runway and backtracking when applicable