SSIS: I don't see the package configuration wizard

It is still available, but hidden because configuring a package is a little different in the 2012 Project Deployment Model. But if you open a package, right-click in the Control Flow tab, click on the Properties of the package, then you will find a Configurations property under Misc.

The 2012 release of SSIS introduces a new model for configuration and deployment called the Project deployment model. As part of that change, the old way of doing configuration (environment, xml, parent package, registry and table) is not an option. In the project deployment model, you get parameters and environments. Thus far, I think it's going to be an improvement.

Fear not though, the classic way of doing things is still available. Right click on your project and select Convert to Package Deployment Model