In PlatformRacing3 admin pick out a player-made level to host as level-of-the-day just drawing attention to it. I think something like that could be cool for Elements too!
You couldn't carbon-copy the idea (play against Deck of the Day) because it would end up a massive grind hazard, but maybe you could challenge it once for extra rewards, or maybe the Oracle could let you borrow one for two or three games (a 'deck of the week' perhaps).
It could encourage deck diversity, and maybe help set some new trends. It would certainly be good for newbies wont for ideas, because the alternative ways to play other players' decks - PvP or the Top50 - are often riddled with pros ready to beat on poor NoobyJim.
Just a thought.