I'm pretty sure "more and more" is quite informal but I can't think of anything better. 


  ...to warn readers that if you give someone a taste of power, they will want more and more until...



Question: Access control Service and Azure Websites Could not load System.IdentityModel.Services
Answer: System.identityModel.Services is a .NET Framework 4.5 namespace with no .NET Framework 4.0 version. .NET Framework 4.5 is not supported on Windows Azure Web Sites.