Back when I was an unspoiled player, I had many many characters pass through Terinyo and not one of them ever knew that Guth'alak gave a low level quest. I'd cleared the Water temple multiple times before I ever found out about this, and I only found out about it because I read a spoiler.

The first time I entered the town I talked to the village elder first, and he gave me a quest to go to the VD. Then I talked to Guth'alak and he said something like "Aye, Champion, your time will come". Which I took to mean that he had a quest for me later - which he did (Unicorn), but I had no idea I had given up an earlier quest.

Every time I entered the village after that, I talked to the elder first (because I wanted his quest - there appeared to be no downside to taking it), and Guth'alak always said the same thing. And Guth'alaks response made me think - "Oh, of course he doesn't have a quest for me, I'm too low-level". And while I understand why the choice exists from a gameplay standpoint, it didn't make sense from a fictional standpoint, which made it hard to spot unspoiled.

I imagine I might have had a similar experience if I had talked to Guth'alak first, although the Elder doesn't suggest that he'll give you a quest later.

1) Maybe if, the first time you talk to Guth'alak after getting the VD quest he says something along the lines of "I see you're doing some work for the elder. That's probably enough load on your shoulders.", and something similar for the elder.
2) A fortune cookie message that hints at this - possibly more likely if either of the quests has never been done by any player in the high score list.

Lots of things in this game make it obvious "something strange is going on, I should figure out how it works" (the banshee works well this way), but this one doesn't feel like that to me. I think it could be clearer to new players without spoiling it.