I love hunting Teostra if only for its theme. So good.
I do sorta dislike you can't capture elder dragons. From what I understand these elder dragons are, in lore terms, very powerful and potentially destructive monsters. Nergigante and Xeno, which attacks on sight, are a good examples of that. But Teostra, Kushala Daora and Vaal Hazak are perfectly happy to chill with you before you bash their heads in and that kind of stings. I'd rather had seen them as hostile to create that "kill or be killed" vibe. Now I feel like a douchebag for killing them when they haven't actually done anything wrong.