How about 3 different PVP modes:
Single Match (like what we have now)
Ladder Match (you must beat your opponent to move to the next node, a bit like a maze path to get the reward at the end. Loser must try again at the same node for small gold/gem price)
Tournament (you are grouped with other players in your pool, and have a knockout tournament to see who can be the victor, starting from the QF onwards)
Wouldn't it be great if new monsters were to be obtained this way, rather than buy collecting gold from your habitats and crafting a rune every 4 hours. LOL