Just a small thing, but I think it would be good for the Herb Collecting quest if you could offer to forgo any kind of reward (at the beginning) if the old man would teach you how to recognize the herb.
Definitely does not have to become completely known but even if it you could recognize it sometimes it would be helpful, and a good way to gain a foothold in herblore. Even just a temporary boost to herblore so you have a chance of recognizing it would be nice.
I've done the particular quest about 10 times, and I've never known the plant in question. You can work it out deductively, but that always feels very gamey. Even if getting the knowledge beforehand feels too overpowered (and easy to just not bother with the quest), it would still actually be a nice reward at the end. Doesn't solve the problem, but would feel very appropriate.
Edit: Another less powerful approach would be if the old man told you where to find it (You can find it by cliffs, my boy!). That would at least feel less gamey than going straight to the wiki.