Affinity Photo can open RAW files true, it just isn't very good at processing them, so far. Plus Adobe has lens profiles. Apps like DxO and to some extent Capture One does as well. However, Affinity Photo is meant as a replacement for Photoshop, not Lightroom or Aperture.
Apple's Photos App, since it uses the system RAW converter the same as Aperture, handles embedded lens profiles from Micro 4/3rds cameras, but has no other lens profile support. Obviously the framework is there, but Apple so far isn't prepared to do the substantial work of profiling all the available lenses for all the cameras out there, the way Adobe and DxO are. Photos app does have nondestructive RAW editing though, but not all the professional tools Aperture had, nor the Metadata editing and DAM features, which is a great shame. For some this is enough.
You don't have to have everything in one master Photos library synced to the cloud; you can have libraries on external drives, even referenced images. You shouldn't be syncing a large library of RAWs anyway, better to export edited selects to jpeg into another Photos library set to sync.
That said, as a photographer, I've chosen after some experimentation to move to Capture One, as I like it better than the alternatives like Lightroom, even though it is not a complete replacement for Aperture at this stage. Nothing is so far. Truth be told, I mainly tested Lightroom just after version 4 came out, I switched to it exclusively to give it a fair shake, but I just wasn't enjoying the experience overall; the editing module was great, but my workflow has me switching constantly into the Metadata tab in Aperture as I go though a shoot. Also the Auto adjust in Aperture was vastly superior to Lightroom for my images, which involved a lot more work getting my images to where I wanted them in Lightroom. My relatively brief test of the Demo of Lightroom 6 simply confirmed that the modular interface which was getting in my way is still as it was, and metadata still not as good to edit as Aperture.
So, for now, I have an uneasy halfway transition system of importing into Aperture, using its import dialog to add default metadata and import into my preferred folder structure and renaming scheme, while adding Auto adjust to all the images. From there, I add track files from the Maps module using GPS data from a phone app (currently Galileo), tweaking the somewhat inaccurate location data on the map, and then adding specific metadata and keywords to batches of photos. Being able to do this in batches relatively quickly and easily is important. I rate and colour label some like I used to in order to compare to Capture One, then write Metadata to the Originals, and later when I've quit Aperture, use HoudahGeo to write maps data as well.
This somewhat convoluted method lets me add my metadata and GPS data in Aperture while it still works, writing the data including GPS to the originals so the data stays with the files and can be moved across RAW converters & DAMS, before opening Capture One and importing photos in place so I can use its RAW engine and editing tools. That gets around its current shortcomings in the DAM department. In future, maybe Photo Mechanic will take on import and metadata tagging, or Capture One will improve on its recent version 9 release sufficiently to make it comfortable for me to tag in, including during import. As for GPS track data, I'm not sure... HoudahGeo can do it, but not sure if I can tweak the locations easily without data entry. Maybe avoiding Lightroom won't be as easy down the road.
