One thing that helped me a lot when trying to learn other fighters is sitting down and playing a new character for some time… one button at a time. Or playing vs someone, with certain rules in place (no jumping. no fireballs. no specials.)
I think it’s a really good way to force oneself to learn all the different tools a certain character has to offer. Would you consider adding character challenges in this direction, to motivate new players to really investigate all tools each character has to offer? Challenges could be different per character, to force people to investigate the good tools characters have which get ignored in favour of “easier” ones.
Ex: play grave without projectiles. Play Valerie without yellow. Play a character wihout jumping, or using only their A moves.