I think a crucial point in my games are the breaks, when it opens up.
And I think the main difference between 1300 and 1800 is houndreds or thousands of games, and a lot time spent on improving.
I was 1330 online in january , and am planning to get myself 1800 for christmas, and in this period of time I might have 700 onlinegames, 200 blitz, 50 OTB-rapid, 20-30 OTB longchess, 10 hours with a GM, and a lot videolooking, analyzing, help from friends, and more.
That sounds like an unrealistic leap in a year, but I have some background. I did compete 37 years ago.
This is why coaches tell their students to open up the position and play tactically against stronger opponents, as opposed to trying to play positionally and getting crushed by sheer experience.
That sentence kinda doesn't make sense.
Coaches recommend seeking out stronger opponents because you will learn more from their play than you will from one of equal or lower rating.
Coaches recommend playing for open positions because its easier to hang material or lose to simple tactical shots than it is in closed positions; the idea is to encourage you to learn elementary tactics and the importance of safety through experience and post-game analysis.
I think you are mixing two ideas together to make a soup that doesn't quite smell right.
I agree. The open game is going to involve more tactical themes like forks, skewers, X-rays, etc. than a closed or semi-open game will. That doesn't mean it's less complicated just that the open game has straightforward tactical themes related to control of open files, king hunts and piece play.
The closed games requires more understanding of pawn structures and breaks, bad bishops, the nature of doubled, backward and isolated pawns and other nuances. Eventually a closed position is going to open up and turn into a semi-open or open game. Being able to handle the open game is then going to be critical.
It also makes sense for a student to know what open game they want to get into when the position opens. Otherwise they are just trading pawns and breaking the position open only to find out they don't have control of the important things in an open position.