My question is why didn't Pickett have a problem with the plan before they marched across a mile of open ground into the teeth of artillery?
Longstreet knew what was going to happen.
Others might disagree with me and they probably have more knowledge of the subject than I have.
Is it fair to say Pickett just wasn't the visionary, the military prophet, or just the smart, experienced guy that Longstreet was? That's a question on my part...
I think we could infer, though, that Pickett was a loyal officer and had this thing about following orders...
All just my random thoughts... YMMV.