[To be clear: I'm not against other courses, but I do have strong opinions about the windward-leeward course]
I have to disagree that "...the aim of the upwind-downwing is to have a lot of tacking...".IMHO, the aim of a windward-leeward course is to maximize the benefit for tactical sailing.
A narrow course reduces the tactical options so that the race becomes essentially a zig-zag "drag race" as everybody simply tacks back-and-forth across the lane to the top mark. I will grant that it favors sailors with good tacking and gybing skills.
With more freedom, a sailor who is paying attention of wind strength and direction variations, the surface roughness across the course, and all the other variables that can occur on a large sailing area has an advantage over their competitors who simply sail out to the corner and tack/gybe.
For example, at the 2014 NAs at Ivanpah, there was a section of near the middle of the racing-area that was significantly rougher and softer than the rest of the playa. Avoiding that area was a significant element in doing well.
On one day, rounding the leeward mark and tacking immediately to port was much faster than continuing upwind on starbord due to disturbed wind on the lower left-hand section of the course.
Even in iceboating, where the speeds generally favor fewer maneuvers, it is not uncommon to tack and gybe multiple times to take advantage of wind shifts or ice conditions.
For example, here's a GPS track of a DN race a couple years ago. There is only one upwind leg where I sailed out to the layline and tacked to the mark. All the other upwind and downwind legs involved more than one tack/gybe:
(the wind if from the lower-left corner of the image)