I think when/if Miller gets a clean bill of health, he'll join with Cardale Jones on a dynamic 1-2 punch at the position.
Miller has never played with this much talent at the skill positions. Yes, he had 1-2 reliable guys he could count on, but now you've got a deep and talented receiver core who can open up the field.
Jones has all the spring reps, but he needs to keep doing what he's doing to continue earning time. I think Barrett ends up the odd-man out, but has the reigns for at least two seasons after.
The way Jones and Miller's game off-set one another is so exciting. I literally can't wait to see how Meyer/Beck/Warriner use them.