Just because they're cadets doesn't mean that they're not capable. Saavik was a cadet when she boarded the Enterprise in TWOK, but she wasn't incompetent. Also, recall that they all had ranks. Kirk was technically a Lieutenant while at the Academy. And a few of them, like Spock, had probably served with Pike in other scenarios prior to Vulcan. And as Nebula said, they were not, I repeat NOT, expecting a combat situation.
Also, in regards to the viewscreen window, it was by far the best representation of an actual screen I've seen on Trek. Besides the traditional forward view, I expect that the screen is able to show any angle around the ship by superimposing it. Not to mention that the screen now displays actual information while still keeping the view open, unlike say, TWOK when the forward view had to be sacrificed to display tactical scans.