I found the world to be incredibly compelling and rich, and got really sucked in. The world felt vast, and I spent hours just wandering around and exploring. It was also my first MMO and the thought that I was playing with thousands of other players in real time was amazing.
I didn't particularly care about Titan (it was vaporware from the start IMO), but I've only felt what you're talking about twice since the release of WoW. The first time was in FlyFF - a god awful F2P/P2W korean MMO. It was the epitome of crap but it did let me explore which I feel is something not too present in MMOs nowadays. There is nothing quite like exploring high level zones as a low level, being somewhere you shouldn't be, a constant danger and a feeling of helplessness when you are spotted by a monster.
The second time was recently, in Wildstar. I've had to stop playing it for lack of time but I dearly miss it, it's the only MMO I actually liked since WoW.
I wish somebody was still building games that weren't necessarily 'smart', but were instead 'fun' or 'fascinating' or anything that means something to the player.