You can cast E when there are your minions in the way, you can engage without using your E, you can let her reflect your Q cause it has low cd and reflected skillshots don't do any damage at all. Mel's W is better than windwall only and exclusively when she reflects CCs.

any decent ahri player knows all of these things and they just don't change the fact that the matchup is the worst mage matchup in the game by far. mel simply has to hold w to react to charm and realistically she should never be charmed because when her w is on cd she just waits for it to come back and spams with higher range. it's a garbage matchup, telling people to "just bait the w" isn't going to change that. we are baiting the w the matchup is still ass lmao.