This was a tough decision, and there was considerable internal debate, but at the end of the day we just weren’t happy with how scaffolding was implemented. We felt it didn’t live up to the quality of the rest of CodeIgniter, and until we can have something in there that does, we just didn’t want to ship with it. We were careful not to break any currently existing functionality, and scaffolding will stick around for some time, but the decision was made to move it out.
I’d love to see this get replaced by a more robust solution - and I fully intend to support any other solution that comes up. For what its worth, scaffolding while appearing sexy on first glance, adds nothing to the end result of an application, but maintaining it opened up a host of other issues for us.