Italianbaptist
Informed Casual
Oh man, looking back there are so many great gym leaders in this gen. My favorites though would probably have to be Roxanne because I always liked the concept of the Trainers' School (it only makes sense in-universe). I liked how the school and its top graduate were integrated in this game. Also Tate and Liza because I prefer Double Battles to Single Battles, even though I wasted Solrock and Lunatone with my water-types.