I don't have any references for you. I can only say that I believe it is the card pool that best captures the cards which have been designed under the current design regime (color pie, keywords, power creep)
I’d appreciate any references you might have to support that assertion. Draft I can understand, but why Pioneer as opposed to Standard, Historic, and/or Modern? Because Pioneer is “Modern for newer players”?
Pioneer is the format which best encapsulates the current design zeitgeist. I've never played it either. I only booster draft or EDH, but in order to understand what "mtg design" means, it's best to study Pioneer and booster draft.