I think back to Pettersson's rookie season. Often reported by Botch and Jeff Paterson about Pettersson's practice habits. Always one of the first there, last one off, staying late after working on his shot or other particular skills. So much so that it rubbed off on teammates and soon more were staying late with him, honing skills. Never Loui Eriksson.
If that's the kind of Pettersson that is still there, and I believe it is, he fits the captain archetype of leads by example. Lets his play do the talking. Players will follow him because he's the best player and he puts in the work to continue to be that.
Surround him with the right alternates and it doesn't really matter how good he is with the media responsibilities. He'll get better at it, but in the meantime is anyone going to care if he talks sometimes, and Hughes, OEL, Schenn, etc whoever else talks sometimes too? As long as someone is there.