What if there were certain NPC's in the game who could offer some assistance. I'm not saying they would solve the riddles for you instantly, or even at all. But say you have a strange dwemer contraption you needed to get working. You spend hours with it, trying to figure it out, but you can't. You take it to a mages guild, to see if they can help, and they direct you to someone who is a renowned expert on dwemer mechanics. You find him, and give him some money to look at the contraption. After a while, you return to him, and he gives you his thoughts. Note, he may not necessarily give you the answer there on a plate. Just some hints.
I think this would be a very natural way of giving the player a nudge in the right direction when they get stuck.
Your thoughts?