Wow, Iris being a gym leader is definitely a big surprise to me. She was seen in a recent video with an old man who had a Team Plasma-esque outfit on. Both of them were talking about the legendary dragons. So either:
1. TP actually means well, which explains why a gym leader would work with them
2. We have another evil gym leader (Giovanni, anyone?)
Whichever one it is, I am very ok with it. To have another evil gym leader would be amazing, and the cruel plot twists that would take place if it were the first idea make me feel like this will be a great storyline to follow.