Having grown up in the Church, there are certain details about Mormon history that I have never really thought about before. These stories have always just been. Every once in a while an aspect will jump out at me that I have never considered as an adult.
One thing that has been bothering me lately is the fact that Moroni took back the golden plates from Joseph once he was done translating. Actually, that is not entirely accurate. Despite the fact that we say Moroni took the plates back, he didn't have them in the first place. They were sitting underground for 1200 years, not in heaven. Anyway, I think the common explanation for this is that we wouldn't have to have faith if there was a stack of finely engraved golden plates lying in the First Presidency vault. I don't know if I necessarily agree with this, but this isn't the part that bugs me.
What disturbs me is the lack of conservation of matter. Removal of an artifact from Earth to wherever the angels hang out seems to be unprecedented in the history of the world. God is omnipotent. He doesn't have to beam down here for cheeseburgers. It just seems odd that he would send an angel to physically remove something. Has God ever taken physical objects (not counting humans) from our world into his before? Was the city of Enoch translated along with all of their buildings too?
Secondly, why bother having the plates at all? We know that Joseph barely looked at them; often they were hidden in nearby woods while he translated indoors. He presumably could have made the same translation even had the plates never existed, just like his translation of the Book of Moses. Why mess with the reformed Egyptian and smelting ore to make plates, and laboriously engraving them if they are just going to function as a "faith intensifier" for Joseph?
Are the plates sitting up in heaven or have they served their purpose? If, say, we receive more of the sealed portion of the Book of Mormon, will Moroni have to physically deliver the plates back to the prophet? Why were they okay underground for so long, but now they have to be safe-guarded in heaven?
Obviously, I don't have any answers to these questions. The golden plates are very interesting because of their sheer physicality. It would have been much, much easier for Joseph to just get revelations through his stone, whether he was a true prophet or not. Why didn't he?