Rewards listed now are a joke. If you want teams to spend gems on an event like this you really should do better. Currently there are only 13 teams 'qualified' for tier 1, where you can get a diamond relic, the one thing that made this event worth spending on.
PainDa, Untamable, Vortigern, United Assassins, Prou!!, Australia Rocks, et cetera (tier 2 teams), really don't give a hoot about a chance of obtaining a golden relic chest. At least not when it comes at great expense. They get plenty of these things for free in Mazes and PVP rewards.
There is no carrot here, please reconsider.