Update September 10, 2012
The "War of Heroes" tournament minimum rounds requirements for winning prizes has been reduced to 20/10/5 for 1v1/2v2/3v3 respectively. Please note that we will be more actively revoking/suspending players who collude with alts/friends to boost their wins/ranking.
The next expansion is currently slotted for roughly around 10/31, and will be a content focused expansion (tentatively will includes new story chapters, possibly bonus WoH chapters, new gem bosses, new raid bosses, new WoH cards, new building/hero/tech levels, feature improvements, etc). I will post a better approximate release date and more details regarding the expansion next month when they become available.