Gatlin has an excellent start, AMONG the best in the 100m. Vicaut, Carter, Blake, Collins, etc. have starts just as good. Gatlin's sets him up well for acceleration after 3 or 4 steps, but he's coming up too early IMO, in this race his head was up after 10 strides. Yes he floats in the air, almost pausing and making a conscious decision to drive the leg rearward, rather than having a smooth cycling motion.
Gatlin will never threaten 9.58 in still conditions unless he starts essentially unrestricted roiding again, which he won't do. He's not Bolt, he's not protected. He will never hit 9.5x He will never even hit 9.6x
He could hit 9.7x-mid if everything works out perfectly.