Responsible Developers: Does IBatis help my customer?

Agile (especially the XP flavor) empowers developers a great deal. Being an ex developer turned IM, I am starting to see that this is a double edged sword. It is dangerous to empower incompetent developers.
Incompetence can come in various flavors, You have your garden variety junior developer, who just wants to get his 40 hours in. Or the grand and wise 'architect' who wants to build a unified framework, which will encompass all knowledge. Finally you get the super dev, who wants to do everything his way, because his way is the coolest.
In an agile team, one of the most important characteristic expected from a developer is responsibility.
Responsibility towards his customer, every decision (which build tool to use, which persistence framework to use, which database to use, MVC or just write to the DB directly) taken by the development team, should have been tested against the question "How does this help my customer"?