If you compare iMovie and iPhoto '09 to the latest ones it's a downgrade from every angle. Even GarageBand lost features, you could use plugins before.
I'm afraid they will "transition" users to Photos in the sense they will let you import your Aperture library, and that's it. The app will have 50% of the editing features, because that's what happens everytime a company promises a new version written from the ground-up.