As a collector, i dont really get the idea of them “time limit” stuff, i dont mind ppl getting the same stuff as i have.
Its like, imagen they removed old tier gear from raids once a new expansion came out, what is there then for ppl to farm once they collected everything and start hunting for transmorg?
So many cool and uniqe mount have been lost in time cuz of this “snowflake / we want ppl to play all the time so they dont miss out” mentality.
End of expansion mounts (moose, arcane bird), event mounts (core hound, horde bike, darkshore bat / hippogriff, heroes of the storm promo.) or simple mount from raid or achi (horse / wolf from trial of crusader, black / plague protodrake. MoP CM birds). ect.
Hell, even some cool transmorg have been lost in time (MoP Challange Mode gear, WoD Challange Mode weap, trial of crusader weap, oldschool hunter bow / priest staff from Molten Core), legendary cloak from MoP quest, mage tower artifact skin (druid skin come in mind).
When that is said, your best bet to get this corehound is either (like ppl have typed already):
1: Black Marked Action House: Startbid are 20k for mounts, but, i bet (if other miss it) the price can easy go up to 1-2M+.
2: Blacksmite have a green version of this.
3: Allied race (iron dwarf) can unlock a 1 headed core hound, its small, but still cool ^^.
Sure some of the item i typed before about been “lost to the time” can be gotten via BMAH, still, if the item is still ingame, howcome they cant just be at thier usally self drop?, i dont see how paying 5M+ gold beats doing naxx achi for the black proto drake.
Hell, it even make me feel bad sometime, when i ride some of those “lost in time” mounts when helping new player, they be like “wow, thats so cool, wish i had it” and i have to tell em “sorry, blizz removed them”.
Edit: Checking thier online store, your even able to buy the WoD and Legion collector edition stuff for 15 eur, why dont they make the same deal for all prev expansion stuff then, i dont mind getting that for vanila, TBC, wotlk, cata, to get them pets :>