[minimaxir]

It should be noted that Hearthstone's odds are not stated (in the US): they were only found out by user research, and as a result of Apple's new rule, would likely need to be explicitly disclosed.

In contrast, Fire Emblem Heroes has always been upfront about the odds, and you can see the odds whenever you want. (although in my personal experience the 5 star odds are less than 6%, hmrph)

[ThrowawayR2]

As the link notes, Blizzard complied with Chinese law regarding posting odds and posted a page on their Chinese Hearthstone site (http://hs.blizzard.cn/articles/20/9546) stating that, on average, 1 legendary card could be expected for every 20 packs (of 5 cards).

It is possible that Blizzard uses different odds by region but that seems unlikely.

[minimaxir]

Fair distinction; added edit.

It would not surprise me if odds were indeed different by region. It would be smart to do that, anyways, since player behavior may be different.