The Tome of Darkness for the Elves? Now, let me share my opinion. You can only hope for artifacts with the Elves and Mages (and it's clear why). The strategy you devise before the game shouldn't be based on the idea that "Oh, it would be great if I got the Tome of Darkness." And what if you don't get it? So, you shouldn't rely on artifacts for the High Elves; if you get one, that's great, if not, who cares. In this regard, the Elves are more flexible because they can rely on artifacts and not just any artifact.
A super ability?...They won't even reach that point...At least not in the Heroes of Might and Magic III.
But the more difficult the challenges, the more interesting it is to overcome them, isn't it?
I don't believe (and I haven't lost much playing as them, so I'm so confident in this race) that the High Elves are as they are described here, and that's why I'm trying to prove the opposite, but, as I see, it won't work =(. I know all the shortcomings, but still...I try to be an optimist. If anyone thinks that I'm writing nonsense, that's fine, but this is just my opinion, take it as you like.
Sincerely, shaddar.