I've got to mage guild level 10 on 11 characters on Xbox EU.
Haven't done it in a while, as I've bought it on other characters.
Recently started on Xbox NA and I forgot how terrible this is.
Firstly, compare it to fighter's guild. You level that up as you go about doing whatever, fighting stuff and playing the game.
Compare that to Mages Guild where you have to drop what you're doing and go our of your way to get books.
Without an external guide (and no add-ons on console) I honestly think people would take months and months and months to level this. That's not a good design for an aspect of the game. Some are tucked away in places nobody would go.
And then compare it to Psijic. Where you have an area you know to explore.
Mages Guild is long and boring. I know we have the daily quest, and that's nice, but it's 3 books. It still takes forever.
We've had a lot of QOL changes in the game, to make things less of a grind so we can play the vast amount of other content the game now offers.
I'd like to see Mages Guild get revisited and make it way less of a grind. I can get a character to 50 before I can do Mages Guild.
Even if it's just more xp per book. People who still want to finish them off can, but you need like 200 books to max it, which includes completing full collections. It's not engaging gameplay in the slightest.