Why "Dreaming high"?
Because I'm suggesting something that I suppose that isn't easy to implement.
Since Defenders' sets are supposed to focus on defense, the shield should be the most important part of them.
So, i think that could be interesting that, when using a piece of Defender, you starts to select a shield instead of a weapon.
What it means?
When using a piece of Defender, the Next Weapon start to work as Next Shield. The mechanics are reversed: Instead of one shield and multiples weapons, you have one weapon and multiples shields.