I don't believe Blizzard would do this, but I think Blizzard should implement a scaling pet taming challenge that scales to the level cap each expansion. It needs to be solo'd so maybe a scenario or class quest, and I think the pet should bring three raid buff/debuff (two known and one random). As an ultimate pet taming challenge I believe that the pet should be a dragon whelp with a breath special attack. It needs to be sufficiently hard, so that at the beginning of each expansion only highly skilled hunters can get it, but as the expansion goes on gear can compensate for any lack of skill.
How would you implement an ultimate taming challenge?