Tortollan Primalist just escapes bottom 10.
That card is so tough to judge. I think it might actually be kinda good but only in Mage. It's probably trashcan tier in every other class. So like I'd give it a 3 maybe even a 4 for Mage but 2 or 1 for every other class. Does that average to a 2? Or just 1? Hard to say.
In Mage there is a pretty damn good chance you're gonna get direct damage, card draw, a secret or an AoE effect. There are 32 mage spells after the rotation if I counted correctly.
All of the AoE's won't kill your dude and will benefit your board (somewhat, even arcane explosion is 1 free damage). The card draw is ok. All the secrets are at least somewhat beneficial and after rotation there are something like 8 of those still. So that's already a 1/4 to get a good effect that is strictly beneficial. There are about 8ish direct damage spells and since there are tons of options of where those will go you can't really say. And since it's discover you at least get to pick your poison. The variance is big, but you can control it somewhat.
On an open board, I'd weigh the card something like this:
40% Strictly good outcome, kills opposing minions, draws you cards, etc
25% LUL Memes. Either it kills itself, hits your face, etc
35% does nothing. Casts spells that whiff due to no targets or whatever.
So yeah it's probably still bad in constructed, but in arena I'd DEFINTELY pick this as a Mage.