It's clear they are putting everything into Photos and so this makes sense. Big question is what they do with all the edits/metadata/etc that people have invested in Aperture.
I think photos will be even simpler than iPhoto. Or maybe simpler in many ways, more features in others. Hopefully it will be nice and lightweight. OS X needs that. Both iPhoto and Aperture were sluggish and their whole interface was just so heavy handed and complex.