Very excited for this tournament, especially as it gives lesser played tiers a bit of the spotlight.
I am eager to watch how this all gets managed, because it appears like we'll be running five full-sized tournaments just to qualify for the finals. This might be a weakness in the way that the tournament is set up, but as an official tournament, it seems unlikely the numbers in signups will be kept to a minimum. I think this first one will be a bit of a learning process and the format will be edited for Grand Slam 2
Best of 1 in the opens would make this much more feasible, even if it means some of the "best players" in each metagame might get cut down early, if they intended to qualify for the finals they would have another 4 opens to get their points in. Best of 3 (in the Opens) seems to be putting too much importance on the individual opens and stretches this massive tournament out even longer.