So basically no reason was given by Wix other than they have newer separate application for the new model. Which leads me back to the part of my previous post that wasn't quoted, and led me look closer at the 5/7002 for the 2015 as compared to the previous Mazda 6 filter.
Originally Posted By: sayjac
....As for the Wix. Wix relatively recently changed the base plate geometry of a number of applications to provide better thread engagement and gasket seal of 'their' filters. The 57356 (for Honda) superseding the 51356 is one such an example. I mention that because the spec'd 5/7002 has a very similar/same baseplate design to the newer 57356. Similar to new Honda application this could explain the newer Mazda application. But this is Wix specific change, others including Fram and Purolator made no similar change.....
Looking at previous 6's, Wix also calls for the 57002 in the 2014 which according to their description is not sykactive. So the idea that it was created just for the 2015 model doesn't appear correct. However in 2013 the 6's filter is the 51348 linked below. It's base plate design looks very similar to or the same as the previous Honda filter (51356) which is discussed in the quote above along with the reason for the change of base plate configuration.
http://www.wixfilters.com/Lookup/PartDetails.aspx?Part=51348
http://www.wixfilters.com/Lookup/PartDetails.aspx?Part=51356
Now comparing the new 57002 to the newer Honda (and others) 57356, their base plate designs also look the same.
http://www.wixfilters.com/Lookup/PartDetails.aspx?Part=57002
http://www.wixfilters.com/Lookup/PartDetails.aspx?Part=57356
I'm thinking that similar to the new Honda filter application Wix also changed the baseplate for 57002 for the same reason, better thread engagement and gasket seal. Wix must have felt they were having an issue with that in some of 'their' previous designs.
But just as Fram and Purolator didn't have to change their 7317/14610 filter spec for Hondas and others, the current 6607/14612 is the correct Mazda 6 application as listed on their respective filter look ups. If I owned a 2014-2015 Mazda6 I'd have no problem using the 6607 or 14612 application as spec'd by either manufacturer.