I see your point. The only reason why I can find most of the quests and progress to 100% is because I've played each update till completion and know where everything and everyone is.
They used to include a walkthrough pdf with each update, but stopped when they implemented the "arrow pointing to the next person to talk to" when you have selected a quest. I can see why they preferred this method of help over the walkthrough, since it's a lot less work, but the walkthrough included a bunch of secrets and easter eggs that would be pretty hard to find if you didn't know what to look out for.
As it is, you really have no way of knowing who has the next quest available or who the next person you have to talk to is when you have completed a certain quest. Might be the bloke in the next room, might be a guy hanging out in the right school corridor in the afternoon on a Wednesday.
Now, those are quest nitpicks. The game is great, story-, gameplay- and art-wise(barring a few frustrating minigames, but it's forgivable). I just really liked the walkthrough pdfs.