Not sure if this had been suggested before:
It would be great if we can search for a specific player and PVP against them. Now to pacify the devs, it would take an X amount of gold/gem to battle against this player. If it's free, I'll take it!
Players can bet gold before they agree on a battle.
Higher level players will need to be nerfed down closer to their lower level opponents (similar to the Challenged mode), including the stars.
What's the point?
* So you can battle against specific people with specific defenses
* Bragging rights
* Make more gold
* Make PVP more interesting
Of course the downside here is people can intentionally setup a game to lose so their friends or guild members can get gold easily (if there's a gold betting). Maybe take out the gold awards (trophies might suffice?)