The "power sharing" can change, and has. Paul VI allowed bishops a great deal of leeway, especially in the Episcopal Conferences. JPII reigned that in. Many cardinals desire more of a voice for the conferences again.
Just depends on how much trust the Pope has in his brother bishops.
It's that trust in "brother bishops" in the U.S. that has brought diocesan bankruptcies, pederasty scandals, nosediving church attendance, and liturgical abuse. The present crisis in the Church calls for a lot less collegiality and a lot more Catholicism.
"Just depends on how much trust the Pope has in his brother bishops." - based on what comes from the American Bishops, I'd say any Pope would be a major fool or schismatic to trust them at all. Look how they have totally failed with the pervert priests - too many involved Bishops were active 'enablers' of the perverts.
They want "more of a voice" so they can issue blantantly heretical statements and ignore the Vicar of Christ with impunity.