Consider the "greater" type of potions that we have available, such as greater bull's strength, potions of the Sage, of the Erudite, and so on. Ingredients for these - especially Serf Grub and Liar's Tongue, but the others as well - take a very, very long time to acquire, and they are also rare to find on their own. In practice, it means that the time investment into even one potion of this variety can be in the several hour range of simply gathering ingredients, and then possibly gathering more ingredients if one fails the crafting roll.
I think that the spawns for these ingredients should be reviewed, so that these potions could be made more accessible and more available. This is not a problem that extends outside of the Greater Animal potions, in my experience - the other high-tier potions have a good balance of ingredients available to them. But as it stands, this specific area of potion-crafting is all but inaccessible due to the scarcity of materials, and the time investment means that players are highly unlikely to even want to use them. I think that there is a better balance to be found there which would allow to see more use of these potions in live play without making them too numerous.