I like this idea. This is probably the best idea out of all the recent announcements I have heard. When it was being more heavily advertised I read the person who created this has been patiently waiting for its release. (No idea if this was true or not..) I'm not entirely sure why the company held out on this but happy to see it actually implemented. It gives incentive to actually be subscribed. Which WoW is facing a lot of competition with F2P games or one time purchase games with no subscription. I honestly don't believe OW2 would've been as successful without it being F2P. Not sure how it worked out for them but could've been potentially worse.
I like this idea too. Lots of these mounts don't have the new flight feature people are raving about. In fact quite a bit of them look like ground mounts with no capability of flying period. I would like to see some newer models in the future if possible too, maybe request more currency? Still transmog items, customizations sound really fun too. Hope they take it into consideration.