Apple is migrating its photo-processing functionality over to the generically named "Photos", which is intended to wholly replace iPhoto and Aperture by the end of 2015. Photos is yet another step Apple is taking toward merging the way its programs work on computers (under OS X) and hand-held devices (under iOS). The program called Photos will run much the same way on your Mac that the app called Photos will on your iPad. At least that's the plan.
Furthermore, Apple evidently intends Photos to be the one and only image-processing tool it makes available to its entire range of users, from grandma's vacation photos up to intensive high-quality professional work. That's quite a range of capabilities to try to cram into a single program, and Apple will have to strike a delicate balance to deliver the desired power to the pros without overwhelming the neophytes.
Still, many people who've been frustrated with iPhoto's unreliable and utterly opaque library — which can produce a gargantuan file with all your images stored in it, God only knows how — will keep their fingers crossed and hope that there's a clear migration path over to whatever Photos will use as a storage system, hopefully one that gives the user more of a peek at (and control over) what's going on.