I know this might sound slightly weird as a request, but why not run these sets as draftable formats on MTGO on occasion? They are well-crafted masters lite experiences that often feature some new art as well. Obviously they don't serve the same function here as they did on Arena helping fill out the card pool, but I think that stuff like a more powerful Kaladesh draft environment could be fun to draft sometime on MTGO. I know flashback drafts and such happen occasionally, so maybe something like this could happen as a "flashback" or sorts to Amonkhet or Kaladesh.
And if the draft formats simply aren't possible, getting the unique art for some of the better known cards like Prophetic Prism or Collected Company would still be cool.
And if the draft formats simply aren't possible, getting the unique art for some of the better known cards like Prophetic Prism or Collected Company would still be cool.