Shadowverse

I agree only about Bramble.

I'd agree with that too. In the current Sword & Sorcery, I'd also agree about Lumina (Albert was used in the old version). Ozya > Illusionist, Ectar > Catacomber, Belfiq > Sabertooth, and so on. In a game where you can put three copies of a legendary into your deck, it's not surprising.
On the other hand, I like Blizzard's approach to legendaries, that a legendary should a) do something, not necessarily super powerful or game-changing, but definitely unique, not similar to cards of a lower rank; b) depict some significant character from the lore, preferably a named one. In Heroes of Might and Magic, neither of these is observed, which diminishes the significance of legendaries, not from a gameplay perspective, but in terms of perception/aesthetics, or something like that.