Erm, she's already shown a huge amount of progression and maturity. Hello "Dear John". Hello "SAFE AND ****ING SOUND"!! She doesn't need boring indie signifiers with meaningless and pretentious lyrics. That's called regression not progression.
Looking forward to that if it makes the album. It'll probably be a bonus track though I don't think she loves co-writers too much.
It'll be the 'If This Were a Movie' of the new album.
Well, she has stated many times that this record will have alot more co-writers, and even some collaborations. So don't be surprised if several of the tracks have been co-written with other writers. There might even be a few duets on there!