It seems to me that the communication breakdown here is:

Star Wars fans loved seeing the established characters who helped connect the dots of the overall story; didn't have problem with new characters' development.

Casual moviegoers didn't need to see overall universe's dots connected; were disappointed with new character development and would have rather spent the time on that.

Fans loved finally seeing a live action Saw Gerrera. To moviegoers, he was little more than a time consuming plot device.