Bratback - I'm certainly not advocating hiring only spotters! I have no interest in "collecting" tail numbers or registrations, I have no model aircraft (not that there's anything wrong with that!) and my bookshelves have only a small aviation section. But at least I have an aviation section!
Where does in-depth knowledge that isn't in the MATS/MANOPS/local orders matter? Okay, let's say a pilot requests direct "high key". It isn't taught at the College... Old Q codes aren't taught anymore (and QFU isn't rude)... Why are the pilots of a 747-400 busier than the pilots of a 747-200 when an engine fails? Why do 777 jockeys complain when given "160 knots to 4 miles"? Why do you have to give speed reductions really early to A330-200 crews? Why do some Beech 1900 operators have a 180kt speed limit below FL100? Why would most crews prefer on orbit downwind followed by a 10 mile final instead of no orbit and a 16 or 18 mile final? Why is a smooth landing on a wet runway a really bad idea?
Maybe bratback can answer all of the above without reference to books or even having to think much about it. If so, I'm glad. But there are those who don't have the answers at their fingertips and who have no interest in gaining such knowledge.