I'll add another one:
Make Old Amber tradeable.
There is more of a market for event vouchers now than ever before (it really helps new players to get money for bike, surfboard, etc). Every single item from the Prize Corner is tradeable, except for Old Amber. Why? I can't imagine this was intended.
The market for vouchers would grow even more if players could trade for Old Ambers and go for epic/shiny Aero's.
Perhaps most importantly, making it tradeable will protect players from being scammed. Currently the seller has to buy the Aero then trade it. The seller could easily just keep it because it's good, or the buyer could easily just not pay because it's bad. Fortunately this has never happened to me but I have heard many stories of this happening before. Because of this, in its current state I would never buy an "Old Amber" from another player. BUT, if the Old Amber indeed became tradeable? I would buy it and I think many other players would, too. It would be the hottest item for players to sell from the Prize Corner, by far I think. And we'd start to see more good Aero's in game, which are few and far between.
NOTE: It appears the reason this item cannot be traded/sold/held is because it is listed as a 'Quest' item. I imagine it shouldn't be difficult to move it to the 'Other' category, where the Eggs go for example.