Thank you!
I also recommend looking into reintroducing removed mounts, and in a way that makes their difficulty to obtain them equal to or greater than original. It’s a great way to give new and returning players a shot to grab the mounts without giving some players a feeling that their efforts were diminished.
Please make it something unique, truly unique or very special and can fly.
After Ion response, looking into mounts in general should be a good thing for collectors, we don’t get new achievements because this philosophy around removed content and promotions as mentioned by Ion.
Please add the current Gladiator mount model to this achievement. (With or without armor, I don’t mind. And with different color ofc.)
There’s no other mount in the game like that.
Honestly a Yeti is fine, just make it celestial and able to magically fly. Or something else if fine to, but for 500 mounts it should be something special.
What I’d love is to see mounts reworked to following.
Base type & variant.
What does this mean? Well think of artifact weapon system. You get the weapon, but then every skin for it, is a sub type of parent.
Imagine mount journal where you click on cloud serpent and under it is all the variants you unlocked.
you can then take collect achievements and break it down by same.
Collect x base form mounts, and this would be one that is easily tuned around a specific target of needing at least one of every type for example. Far as I know game has never had any mount type removed. variants but never a full erradication. black proto for example is gone but protodrake type has and never will be nuked.
The second achievement type would still be for variants but in a far more interesting meta type way “collect at least x protodrake variants, cloud serpant variants, etc” and when you meet criteria of variants, which would consider how many were removed, complete the new meta achievement. That would also be more interesting.
Anyways, it’s more work but I think is far more engaging than ever inflating undertuned count.
Hopefully it’s a cool mount. Maybe unique model wise. As 500 mounts is certainly a high number and long commitment to the game.
Devilsaur!!! Please for the love of the Mankrik’s wife make it a Devilsaur. Yes i said it already but just felt it needed repeating.
hell hath no fury like a mount collector scorned
this is excellent! thank you!
also whoever came up with the name Mister Muskoxeles is a genius, a hero, and deserves a big fat raise.
Next can we have achievements for 600, 700, 800, 900, and 1000 mounts? 
Hopefully, y’all can use one of those super unique and cool future-store mounts as the replacement for this achi instead of putting it in the shop. 
At the end of the day, does it really matter what mount is given by the achievement? I don’t even see the 350 or 400 mount rewards used, even in no-flying areas, and those ones definitely stand out from the crowd. Which gives the impression that by the time a collector has this many mounts, they probably have one from somewhere else that they prefer using anyway and the achievement rewards are just another checkmark in the collection UI.
You’re really struggling with that post, huh, buddy? 
It’s okay. 
That’s a ridiculous reason. The whole point of achievements like this are to reward the players who go after those types of mounts for the achievement. There’s no prestige anymore in anything.
I will say I think it’s weird that battle pets of all things got four new achievements, capping off at 2,000 unique pets (which isn’t even achievable yet), while both mounts and toys only got one each and they cap off well below what players can already obtain.
I think 500 is a big achievement, that requires work to do and the reward should be equal to that work.
It doesn’t have to be a new model but it has to be something really cool. Something crazy like the firehawks from the fireland in a different color, like a blueish flame. Something that catches the eye and goes like, “damn” - I want that for those aspiring mount collectors.
True!!!
We used the mount among the collector community during mount competitions, I usually change between my rare mounts on BGs, Arenas or afk at cities.
Exactly, the game should incentivize mount collecting instead of fearing the players reaction to a “bar so high”.
But…given the nature of the collector community, wouldn’t everyone already have the achievement mounts already? The totals are certainly low enough that most of them are basically ‘free’ nowadays for anyone who’s actually interested in collecting. It’s gonna (for better or worse) generally be the rare-drop mounts like the MoP world bosses or stuff that’s both unobtainable and was difficult to acquire when it was available EDIT: or is just extremely old like the original epic mounts that stands out in these circles, not collection achievement rewards.
I think it should be like a jetpack or a broomstick.