Only lately have I been using FRED2_open. Did most of my playing around in the original FRED2. Looking through some of the stuff I see things that make me cringe from the old days. Wondering if they are still a problem.
Nested when statements: These were to be avoided because there was never any telling when they would actually fire (especially in multi). Chained events or using is-event-true delay was preferred.
Ship vs Wing orders: Again in the old days you were always told to avoid individual ship orders if they were part of a wing. This was weather or not there were wing orders.
I'm sure I'll come up with some others as I get back into playing with FRED.