Eeehh... but herbalism is different than the other crafts. We aren't making something that's going to last a long time. This isn't the endgame fullplate your character wears until he dies of old age or trips and falls onto a rust monster. Invisibility, Freedom of Movement, Expeditious Retreat, and Death Ward do not feel like endgame prizes you should be working your ass off to get to. In fact, I've never seen anyone even use a Freedom of Movement or Death Ward potion, so they can't be THAT widespread. The current prices of some of the potions the top herberalists are making keep practically anyone from wanting the stuff (and possibly causing more people to probe into the herb world to find out).
I think what we have right now on what I'll call the "lower echelon" of herbalism is fine the way it is. What I think we're missing is an upper echelon. I think we should be seeing some DC 40-50 potions like stoneskin and possibly even something like a lesser spell mantle, but with great scarcity. How cool would it be to stumble upon a dusty old book resting on the top of a book pile in the alhoon's lair, describing a legendary brew that makes one's skin hard like rock, and that the ingredient is only found deep withing the depths of the caves at the summit of Baratak. Go on expeditions to find this ingredient, or maybe pay mercenaries to find you that elite vampire heart you heard another legend about.
I think herbalism needs something akin to the white stag hides and antlers that can be used in smithing and bowyering. Right now there is no secret ingredient that makes everyone go wow. Maybe it could be something as simple as dropping a vampire heart into the cauldron makes all brews more effective, but raises the DC by 15. I know the in-game description of herbalism describes that plants, fungi, and animal matter are all parts of herbalism. I also know that I've gone completely insane before throwing practically every animal and item in existence into that cauldron trying to find some secret brew. I think I've thrown everything in aside from white stag antlers themselves. Coldstones, alchemist's fires, crag cat pelts, winter wolf pents, musk ox horns, musk ox pelts, bear pelts, snakeskin, small snakeskin, rats, dire rats, mink pelts, meat, food rations, and many other things, but to no avail. I end up emoting that the cauldron looks like a polluted lake with corpses bobbing on at the surface of the murky water, and I'm using my ladle to try to keep those bloated rat carcases below the surface.
Mystery, legendary brews, and adventure! I think these things are missing from herbalism and could easily come along with much higher DC's (and fun) than we currently have. I don't have a problem with the way herbalism currently is, because it feels right. In comparison to the other crafts like smithing which require a lot more time, it feels a little wishy-washy, but I think some of the suggestions I've given could easily fix that while still leaving what we currently have exactly the way it is. Though I guess it must be worth noting that any mystery added to a craft only lasts until one or two people find out about it, because then practically everyone will know.