Raw DNG is no more a standard for sensor data than MKV is a standard for video encoding.
In other words, raw (as opposed to linear) DNG is basically a container format for sensor data and related metadata. So even assuming Adobe's DNG converter perfectly supports your camera, you still need code to handle its underlying sensor data format (your Bayer demosaicing code won't be much help in processing data from, e.g., a Foveon sensor) and whatever mandatory image correction it requires (e.g., many cameras and lenses rely on software correction driven by camera- or lens-supplied metadata, and will yield heavily distorted images if this correction is skipped).
In other words, until camera development stagnates, raw processing is a moving target by its very nature.
With that said, AFAIK, Aperture uses public OS X APIs for raw support, so potential Aperture replacements on OS X can get up-to-date raw support "for free". Given that Photos will support camera raw, this announcement gives me no reason to believe Apple won't continue to add support for new cameras in future OS X updates. Which is not to say Apple will support as many cameras as Adobe, of course — I'm pretty sure they already don't — or that support for new high-end (think $20K+ medium-format, not Nikon DSLR) camera support will decline now that no first-party professional software requires it.
I think (generally speaking, for most people) that Linear DNG using the Adobe DNG conversion method asked about is probably sufficient, if inconvenient. Most people I know who shoot RAW do it for the high-bit-precision dynamic range and white balance adjustment capability, both of which Linear DNG preserves.
But there are very valid reasons not to want to settle for partial-baked DNGs. Personally I was converting my CR2s to DNGs at Lightroom import for a couple of years (since DNGs compress and take up much less disk space) but regretted that when Canon's DPP DLO got really useful and I was unable to easily get those DNGs back into DPP as RAW.
Now I'm a big fan of saving the actual camera RAW file as the 'digital negative' even if that means the files are bigger and the format is more likely to be 'obsolete' in the future (there will always be older versions of Adobe DNG converter and dcraw to use if that is ever a real issue for me).
In other words, raw (as opposed to linear) DNG is basically a container format for sensor data and related metadata. So even assuming Adobe's DNG converter perfectly supports your camera, you still need code to handle its underlying sensor data format (your Bayer demosaicing code won't be much help in processing data from, e.g., a Foveon sensor) and whatever mandatory image correction it requires (e.g., many cameras and lenses rely on software correction driven by camera- or lens-supplied metadata, and will yield heavily distorted images if this correction is skipped).
In other words, until camera development stagnates, raw processing is a moving target by its very nature.
With that said, AFAIK, Aperture uses public OS X APIs for raw support, so potential Aperture replacements on OS X can get up-to-date raw support "for free". Given that Photos will support camera raw, this announcement gives me no reason to believe Apple won't continue to add support for new cameras in future OS X updates. Which is not to say Apple will support as many cameras as Adobe, of course — I'm pretty sure they already don't — or that support for new high-end (think $20K+ medium-format, not Nikon DSLR) camera support will decline now that no first-party professional software requires it.