Disclaimer: this entire post and community discussion is based around datamining and related conjecture. Nothing as of yet has been confirmed or denied by Blizzard themselves; we have no idea what the future will actually hold in regards to their plans with this item. Most importantly of all, this is just my own opinion.
I personally disagree with the Kor’kron War Wolf being added to the Trading Post, however, I agree that it and all other AotC mounts should be accessible again.
There has been a precedent set since Siege of Orgrimmar that each final boss of an expansion will reward a mount for achieving Ahead of the Curve. The mount is and has been the reward and goalpost for non-Cutting-Edge raiders.
I believe putting AotC mounts on the Trading Post completely disenfranchises the achievement of getting Ahead of the Curve. (Yes, specifically the KKWW could be awarded from Flex, or Normal, as well as Heroic, but this has proved to be an outlier.)
Between lackluster M+ mounts and genuinely difficult to achieve once-per-expac Cutting Edge mounts, AotC mounts fill a perfect reward niche for most people.
PvE-centric mount rewards are already few and far between, however. I would be a huge fan of bringing these mounts back, but is the Trading Post the right way to do it? I don’t think so myself. This is more about the elimination of prestige from AotC than it is about AotC mounts becoming available again. The idea I’d suggest would be treating AotC mounts in a similar vein as Vicious Saddles, something like this:
Each time you achieved Ahead of the Curve- no more than once per raid tier, of course- something like a [Vindictive Bridle] would be awarded to you. This Bridle, or mount token, would allow you the choice of any past or current AotC mount. If you achieve AotC during a tier that also otherwise would award an AotC mount, you must choose between the “current” mount or getting a token to choose one of the past mounts.
This solution would open access to past AotC mounts- which is a good thing- while still preserving the requirement of getting Ahead of the Curve. Recolors of AotC mounts would be a completely appropriate area for the Trading Post to cover, however.
Let me know what you think!