-snip-
I dunno... Most of this seems like the classic fan card stuff that comes up again and again. +Action tokens, -Action tokens, giving other piles the Treasure keyword. I seriously doubt Donald X. hasn't already considered and ditched most of these things.
On the topic of predictions I don't see coming true:
-Repeating old component-dependent mechanics (reserves, tokens, ruins, potion)
-Alchemy II, although this is pretty much a no brainier.
-Weird supply cards like Black Market, or Co0kiel0rd's Secret Society. Confusing. Maybe as another promo though.
-Generic messy rules stuff, like giving other types to cards.
-Team rules/cards.
-A new type of Landscape card.
-Another currency.
There are some things that I've seen in fan cards that could come true:
-Putting cards on other supply piles (like Kru5h's Rabbits). Spilt piles adds some precedent here, but tricky to work out.
-More funky card combos and dual cards.
-Cards with piles outside the supply, like Murchinary.
-Funky card costs, like 0, 1, 8+.
-Cost Increasing. This might go under the category of funky rules stuff, but it was playtested in adventures before so the scrapped card could live on...
-We now there used to be a different bonus on Wedding that Donald saved. Probably would return, though no clue as to what it would entail.
So far the most recent expansions have been sequels to old expansions, Adventures = Seaside, Empires = Prosperity. If that holds true, Hinterlands, Cornucopia, or Dark Ages would be next up (skipping Alchemy and the updated Base and Intrigue). There's definite room for new things coming from the "when buy" triggers of hinterlands. Villa shows this. Cornucopia was a small expansion and much loved, so new variety cards could come. Who knows? Another card that uses Prizes complete with a new set? Dark Ages also has some room for new stuff. I doubt Ruins would ever make a comeback, but on-trash effects can come as well as other trash-related mechanics. Who knows even, maybe another set of knights!