Ikariam isn't a game that you play for 1-2 years.. It is a game that people play it for more than 10 years now (and counting). Needs of people can change due to these years and the game should give players the option for a change.
Sure someone could use the town relocation, but lets face it, when you have already invest millions in your island saw mill and luxury good it isn't an real option.
You can't leave a saw mill 40++ for something 10 5-6 levels down.. (the same stands for luxury good too)
Someone could also say, that the people should be more carefull in first place when the decided in which island they will build their empire.. But some of us done this choice back when the island miracles had a completely different function (ie, the temple of Ηades gave +20% marble production, athena+20% crystal, gaia +20% wine and Hephaestus +20% sulphur), so it wasn't really our choise..
Therefore, i believe that the game should give players the option to change the island monument..
In my mind is something like that players of an island should be able to begin a vote of a change for the monument.
In order to begin the voting the player should pay something ( either goods, gold, favour or ambrosia)
The voting will go based on the island faith share. In order for the monument to change, the votes should reach 100% conversion - Thus either all players with a temple agree or the ones who want to change the monument should have enought priest to cover it...
When the voting finish, if the change pass.. then the players will have to face the rage of Gods (a countermeasure, in order to avoid overexploration of the new feature). From the mythology we know that when Athenians, decide as a protective Goddess Athena, instead of Poseidon, Poseidon in hot anger flooded the Thriasian plain and laid Attika under the sea.
All the men voted for the god, and all the women voted for the goddess; and as there was one more woman than there were men, the goddess appeared at the head of the poll. Chagrined at the loss of the election, the male candidate flooded the country with the water of the sea, and to appease his wrath it was decided to deprive women of the vote and to forbid children to bear their mother's names for the future.
Based on this myth... When someone votes for another god..then he should receive a punishment from the old god. Also the other Gods (no bonuses from Gods’ Shrine) would not help the cities of the player until he resolves the conflict with the old god.
So, either one week punishement.. or a donation of faith/ goods, gold, or ambrosia (or it could be 1 week normally with a premium option for instant resolution)