clearly they're not putting much work into even though it replaced iPhotos AND Aperture.
Photos does not replace Aperture. Apple is offering nothing at all to replace Aperture. The developement simply stopped without a new professional photo application by Apple. Photos allows us to browse the Aperture libraries, so we can access our photos to migrate to another professional application like Lightroom, but that's it.
Nothing to do with Adobe, this is dragging from Apple Photos to Apple's Safari Browser. The issue pre-dates El Capitan but still exists.
My answer was in response to Network 2's post that commented on Adobe products - dragging from Photos to applications works, if the application has been updated to allow it.
Network 2 wrote: Apple appears to be deprecating drag/drop in favor of the Media Browser. This is based on the fact that where iPhoto supported direct dragging to other applications like Photoshop, Photos does not.