I was catching up on Darth Solo's posts on WoW Alone when he commented in this post about how he couldn't stand questing in the Old World (Classic WoW's locations), and how much better Outland and Northrend are by comparison. That got me to thinking about my own questing experiences; while I can see Darth's point, there are plenty of quirks out there that balance out the questing throughout the WoW environment.
It's no secret that I'm a bit of a quest whore -as Souldat calls me- and I've an ultimate goal of having Quintalan reach that Seeker achievement. I'm roughly 600-650 quests away from Loremaster, and from there only about 100 or so to reach 3000 and the Seeker. For my alts, I'm not planning on being so thorough; there's no need, really, with the exception of the class specific quests. (By comparison, an achievement such as Explorer on a PvE server isn't nearly as impressive as on a PvP server; there aren't many Alliance gankers you have to worry about when exploring on a PvE server.) Nevertheless, there are some major differences in how the quests were designed to push a character along in Classic WoW vs. the two expansions.
Blizzard designed the quests in Classic WoW to push a player from region to region when the appropriate quests opened up. This is still used in BC and Northrend, but instead of viewing each expansion continent as a whole, Blizzard focused more on individual regions. You can see that in the quest achievements themselves; in the Old World, the quest achievements are for each continent, not for completing quests in a given region. BC and WotLK have achievements for clearing each region which add up to the Loremaster meta-achievement.
It seems that in the Old World there were more options for leveling in a specific range, say for the 20s: you could go to Hillsbrad, Thousand Needles, Ashenvale, Duskwood, Stonetalon, Wetlands or even Stranglethorn if you're feeling brave. The breadth of locations to work with means that you can work on your questing as, say, a Tauren and never have to visit the Eastern Kingdoms at all. Blizzard seems to have compensated for this by putting in these oddball quests that have you traipsing back and forth between two continents just to talk to different specific people, who then tell you to go hunt for stuff in an instance. For example, you're in Arathi and you stumble on the quest chain that leads you to Tarren Mill, the Undercity, Senjin Village, Zul'Farrak, and lord knows where else. It's clever on the face of it, but without flying mounts you have to make more connections than trying to get from Atlanta to Anchorage on Jet Blue. The travel time gets to be tedious, and you often start to wonder whether the quest chain is worth it.
Outlands quests narrowed the scope to a more manageable level -and the addition of flying mounts helped tremendously- but there still is a maddening tendency to insert cross region dependencies on some quest chains. This wouldn't be that big of an issue unless you're trying to reach the Loremaster of Outland achievement, where you find you're perpetually short of quests in a region (Nagrand and Hellfire Peninsula are two big offenders) until you come across a quest in Shadowmoon Valley that sends you to those regions.
With Wrath of the Lich King, the quests evolved further. The maturing ability of Blizzard to mix in an overarcing quest chain with the more narrowly focused ones really kept the pace brisk. That was most felt in Dragonblight (Wrathgate), The Storm Peaks (Thorim and Brann Bronzebeard), and Icecrown (Argent Crusade and Knights of the Ebon Blade). Blizzard's fancy phasing tech has a tremendous impact here as well; no more equivalents of killing Dar'khon and then finding him respawn a few minutes later. "Will no one rid me of this meddlesome Necromancer?" (Apologies to King Henry II for that little quip.)
I must admit that the phasing technology has me biased toward the Northrend quests; I found them much more interesting than some of the grinding you feel like you're doing on the other regions. Ironically enough, I like the Outland quests the least. Perhaps it's because the changes were half baked, but I often felt like I spent hours hunting around Outland for an individual quest that would put me over the top for an achievement, and I would spend an equal amount of time perusing thottbot and wowwiki as well.
Classic WoW has a bizarre sort of appeal to me. It was by design big and broad, and the concept of trying to check out everything is a daunting task. The things that Blizzard put in place for Classic WoW may have made sense when they designed it, but the creakiness of the Old World is pretty apparent these days. Yes, I hope that Cataclysm will bring a Northrend style focus to old Azeroth, but I've a certain amount of fondness for the meandering (and maddening) nature of some of the Old World questing.