In my continuing saga of possibly pointless comparisons between WoW and Elder Scrolls, I want to look at sense of world size.
Both games use a "discover it to get there" system. Elder Scrolls: Oblivion has a 'fast travel' system where you can just click on a significant location you've discovered and the game will play out as if you'd run there; passing time, moving NPCs, but taking no more time than a loading screen. Similarly, WoW has flight paths, which are slower, but since you can go afk during them, aren't too dissimilar.
Teleports, whether we call them portals in WoW or fast travel in Oblivion, tend to reduce the sense of world size. As humans we unconsciously measure distances in time. This is why walking a mile can seem longer than driving ten miles, even setting aside the physical labor aspect. When travel time goes down, perceived distances goes down as well. Despite being a big world, the outside of Oblivion doesn't seem gigantic. Imperial City and Bruma, despite being several hours away in game time (this would be 10 or 15 minutes in real time running), are a few seconds away to me. I go back and forth between them often.
Beside the outside world, there's also the inside. In these places, Oblivion is much bigger. Recently I carried out the greatest heist of all time. This involved running through all manner of sewers, then crypts, and in and out of buildings. The distance covered was at least as much as that previous 10-15 minute run, spanning the city (which is pretty wide), back and forth (think spiral, not loop), and over it all again. It took much longer than 10-15 minutes, thanks to being filled with enemies. That wasn't what gave the full sense of size.
I kept trying to find my hearthstone. You think I'm kidding? I was carrying tons of armor, really valuable stuff, or at least my noobish self thinks so, but I was running out of strength to carry it, so I'd keep finding a new thing, estimating value/weight ratios, and dropping stuff. I would have loved to hearth out and vendor some of it. Or teleport out of instance. I needed to recharge my dagger too. The enchant ran out way too quickly. And I was low on arrows.
When you're loaded with loot, barely halfway in, your items are breaking, and there's no quick way out, that's when you get a sense of scale. Location mattered. Maybe the dungeon was a lot smaller than I think, but it felt huge.