Its no secret that ikariam is filled with bot/farm/general bank accounts, with or without IP sharing. Here are some ways i think that would help combat this issue.
1) Burning/Destroying instead of pillaging resources
"Pillage" should be changed to "Attack". When you attack(Pillage in corrent language) someone instead of taking his resources, you would "burn" or destroy his resources. more trops=more resources burnt in his town.
2) Removal of Black Market.
black market is being used for bank accounts to sell troops for gold, that is how people use these accounts to get troops fast while it takes days to get these troops, hence black market gives huge advantage for those who are in continuos fight against multiple opponents while playing alone.
3) Make the Resource Mines more productive and personal.
Add more levels to the island resourse mining, decrease the amount of required resources to upgrade it, make it so each player can upgrade their own personal Island mine that way people wont use alts to donate to the resource mines, and people will individually spend more into creating more.
3.5) I suggested earlier to make Monuments as town buildings. That helps combat alt farming as well as not searching preferred islands for specific monuments
here: Feature Suggestion 3: Making The Miracle Monument as a Town Building
4) Creating More Player Collaboration Events
Events like the Hydra raid could be fired more often, Events that require teamming with other players will revive the game and make the players connect more than what we have now.
people will seek alliances, team, member to fight the events together.
Hopefully that helps, Would like to hear feedback and see opinions from higher rank GOs