The god powers are among the many attractions of the game, so they could be shined more:
Option 1:
As you move into the mythic age, god powers are renewed:
Only if they were already used: ex. bolt, vision, etc., in case of powers that can be cast more times, they recover 50% of this.
The powers that give captured buildings are not renewed.
Similar to the shipments of age 3, being able to renew some of them when passing to the last age.
Option 2:
Being able to request the powers of the gods again from the temple, but at the cost of favor and gold. The more a power is requested, the more expensive it becomes. The powers that grant unique buildings can only be requested once more at most.