For an event like SF, with so many different fleets of vastly different performance, I can definitely see the value in using two separate leeward marks, as opposed to one gate, if there were not enough marks available (something that could also be borrowed).
Don't get me wrong, I would still prefer to have two gates (not critcizing SF, just speaking hypothetically as a PRO).
But, as I've noted in other threads, it's far more helpful to keeping the system running smoothly to separate the start and finish areas when running such a mixed bag.
Now, if one of the classes had 30 boats, I'd find a way to come up with another mark to give them a gate.
As a sailor, I prefer more roundings. So, I typically run more 3-lap races than 2-lap races. Here's the key a LOT of people miss: you adjust the course length to keep the target time the same. So, all of the races actually take the same amount of time (which many, many people confuse with length), but there are more close roundings to develop rounding/crossing tactics, which again, helps in the bigger picture (practice for NAs, etc.).
I make it a point to know my sailors, and some of them prefer longer windward legs to "stretch out" and spin sailors like longer runs, aka fewer hoists/drops (especially the crews), so I mix it up, use longer weather marks for the spin boats, etc.
All of this is great fun to discuss, and there are 1000 ways to skin a cat. All of this hypothetical discussion aside, SF did a great job and everyone came away happy. At the end of the day, that's the true measure of success.
Mike