My theory is there's only going to be 6 gyms instead of 8 this time, we can see 5 of those stadium like gyms on the map plus 1 slightly different looking big one in the big first city, I don't think the one in the top city is a gym but rather were the E4/champion battle will be held.
Also the gym have colours which I assume reflects their type, but the gym in the ice place is black rather than light blue, so possibly finally a dark gym?
Give your thoughts.