Iris/Drayden only had Three Pokemon. If they are still following the same pattern, who is to say that these won't go 2, 2, 3, 3, 3, 3, 3, 3. We know that the first two Gyms have 2 Pokemon (Cheren and Homika), Elesa had three in B/W, although the trailer only shows two, we can assume she has three placing her fourth+, and Shizui's Gym is in some sort of Port city with a lot of docks, there is only one place like that and that's where Undella bay was.
As for Gym skips, that only happened in Gens 1 and 3 as major story elements with Giovanni and Norman (Giovanni being the leader of Team Rocket and neglecting his Gym leader role, and Norman telling his child that he would not battle them unless they had four badges.) Gen 4's changes. You DO meet Fantina and see her gym in Pearl/Platinum while you don't get to challenge them yet, but in Platinum you challenge her when you get to Hearthome so her Gym placement switched.
If they skip gyms, I don't think it'll be Elesa's gym that gets skipped seeing as she was a highlight to the Trailer.
