Apple didn't exactly say they were replacing iPhoto or Aperture, but that they would stop development of iPhoto and Aperture after Photos was released.Richard Serkes wrote:OK, why hadn't I noticed this before? After OS 10.10.3 loaded Photos it didn't delete iPhoto. It's still there in the Applications folder. And if you tell iPhoto to open the old iPhoto library to the Aperture library all your photos are there. So if Photos is supposed to supplant iPhoto why did Apple leave iPhoto? As Ricky Ricardo might say, "Apple, you've got some splannin' to do."
In most past cases, Apple's new-generation software doesn't delete the old-generation software. That goes back at least as far as iMovie HD. The new Pages and the last-generation Pages coexist.
Anyway, I think the strategy of copying selected folders of photos to Photos and then using iCloud Photo Sharing seems viable. That's not any harder than using Dropbox or jAlbum (which makes photo albums you then publish to your own server).