If you genuinely just called Morrowind "linear" I'm wagering you've never actually played Morrowind. You couldn't be further from the truth; that was the best thing about Morrowind - the proverbial could get real at any moment. I understand what you're saying, but calling Morrowind "linear" - that word does not mean what you think it means.
Don't get me wrong, Morrowind is my favourite game ever. Zelda OoT had been my favourite game for like ten years since I got it and a N64 for christmas at age 12. Then I happened across Morrowind in a bargain bin for $10 while looking for something to do in the uni holidays (this was only about three years ago), and I thought it looked pretty good from the pictures on the back and the most I could lose is $10 if it turned out to be crap, but I was totally blown away! It blew Zelda completely out of the water.
When I say linear, really it has about 50 "lines" to follow, which made it not seem like that. And probably a lot of them branch into multiple "lines" themselves by choices you make. But it has to be linear by definition - lots of the caves/dungeons are tied to quests, and the enemies that are in there are at a particular difficulty, because the game expects you to go in there after you've finished certain other missions, which you had to be a certain level to be allowed to do.