I find the prospect of an AI changing people's preferences to make them easier to satisfy rather disturbing. I'm not really worried about people changing their own preferences or succumbing en-masse to wireheading. It seems to me that if people could alter their own preferences then they would be much more inclined to move their preferences further away from a tendency towards wireheading. I see a lot more books on how to resist short term temptations (diet books, books on personal finance, etc.) than I do on how to make yourself satisfied with being fat or poor which suggests that generally people prefer preference changes that work in their longer term rather than short term interests.