Commonly, writers state a "good" character with a powerful arc is someone an audience can identify with. You hear the expression "write what you know" most of the time because you can create interesting characters based on who you've met, exaggerations of who you've met, or a mixture of your favorite pop culture characters.
You need to keep in mind, players lose connection to characters once they feel the character has done something unrelated to their personality or to their arc. Also, in franchises, it's imperative to avoid rehashing "new characters" as alternate versions of previously established casts. For example, in recent Star Wars films, some audiences felt main characters like Rey, Finn, or Poe had too similar storylines to icons like Luke, Han, or Lando. Please note, not all fans felt this way; although, analyzing how fans react to new or old characters in any IP will aid you on your quest to summoning the most powerful emotional arcs, plots, and moments.