I simply loved this piece. The writing, the atmosphere -- it really makes me want to use it one day. I can imagine a religion springing up around Lojcrelt, some sort of "cult of the universe" whose sages seek an audience with the Wisdom. Too bad it sounds like they'd never return after achieving enlightenment. Overall, a Teller's Stone sounds like a worthy quest goal and provides plenty of motivation to seek it out. Once again, I tip my hat to you, sir!
I think that these are interesting from what I think is the intended perspective, traditional fantasy, but I think that they could also be really interesting in a more Harry Potter sort of setting. In the former, they offer some interesting ideas, but I think would mostly matter in their actions and bonuses.
In a game focusing more on wizards, though, I think that they could be pretty neat. Stonepal shenanigans, maybe tubs of water for people to put their Wet One's in when they're occupied. Getting an upgrade could be a big deal - you could even use the four elements as a sort of Hogwarts-style Sorting, actually.
From the perspective of somebody interested in familiars, I think that they're neat.