Apple unveiled the new Photos app for Mac today. It's built into the next point release of OS X, and is the replacement for iPhoto and Aperture.
There seems to be some trepidation about this, but I am bullish on the prospects of the app. To my eyes, the previews I've looked at are promising. I think the app looks nice, definitely an expansion of what we currently have on iOS. All the features we liked from iPhoto are there, even a little more advanced that iPhoto.
But Apple discontinued Aperture as well. Photos doesn't look like it comes close to the fine grain control that us advanced users need. That said, I see no reason why Photos won't support third party extensions. What if Pixelmator made an editing extension that gave you tons of effects? What if, and this is a dream, Adobe made a Lightroom extension that gave you Lightroom control over your iCloud Photo Library?