With the changes to leveling in the near future, being able to basically pick the expansion you want to level in after leaving the starting zone, which expansion do you guys picture yourselves picking the most over others?
For me I’ve always preferred the Burning Crusade zones. Lots of quests packed tightly together and whatnot. Great for things like exp potions, Darkmoon buffs, etc.
MoP is my favorite i luvs the sounds and art 
I think I would have to say MoP as well. It had the best looking zones imo, the overall story hadn’t gone completely off the rails yet, and the pandaren are honestly just a relaxing people to be around.
As someone who started with MoP, it’s my favourite due to its aesthetics and plot. Even compared to newer and older expansions it’s hard to beat.
Second would have to be WoD, which despite its endgame and story flaws, had a fantastic self-contained levelling experience. It’s probably the best expansion in terms of zone-to-zone flow imo.
Legion/BfA fall between MoP and WoD for me because while the questing and individual storylines are really good (BfA over Legion for me) it lacks the zone-to-zone connections that put MoP and WoD where they are.
Cataclysm 1-60 and (formerly) 80-85 are solid overall, a good chunk of the 1-60 zones are just “ok”, some of them are hot garbage/tedious to do (Vashjir, I’m looking at you) and a few are amazing and still hold up (Redridge and Hillsbrad are 2 that really stick out for me, alongside Uldum and Stonetalon). Graphically it’s a mixed bag, since it uses a mixture of new and old assets which can look jarring at times.
Burning Crusade hasn’t held up at all, it’s art (while pretty in places) looks horrendously dated and it’s quests are basically Vanilla 1.5, which means their mostly mob grindfests.
Wrath for me is kind of the weird middle child of it all. It’s got some aspects of Cataclysm’s levelling while at the same time holding onto aspects of BC and Vanilla. And while the zones hold up much better compared to BC, the questing is what really put its off for me.
WotLK for its sense of danger and relevance to the WC3 story and favorite villain.
MoP for its beautiful terrain and great story. The aesthetics and key “moral” of that expansion was amazing.
If I can make it past the PF nonsense, I would choose MoP to level in. The zone design was great and the quests interesting. For the more intangibles, it was soothing with the choice of music and graphics. Overall a very pleasant leveling experience.
Slow down…
I might be the odd man out here, but… I’m kind of looking forward to leveling in Cata zones. Crazy, I know.
Amusingly, possibly, and I’m probably alone in this, but WoD. Thanks mostly to the ease and speed of it. Having a potion available, sending minions out to retrieve XP, and tearing through Bonus Objectives makes it go by FAST.
I wanna redo WoD leveling after the revamp too… but not just because its fast. I haven’t replayed any zone except Spires because it is so quick to just use bonus objectives and then Spires + the inn XP buff. Once everything scales from 1-50, it’ll be fun to revisit the storylines of Shadowmoon and stuff, because they were pretty good.
Pandaria 
the only one i feel i havent done to death is cata. by the time i can do those zones with an alt, they’ve hit the next xpac so i dont bother…
leveling would be a billion times better if half of it wasnt spent traveling to where you want to go. taking an fp from IF to aerie peak alone is FOUR minutes… More portals are needed, not less. 
Or perhaps some method for having the player directly control a faster and more efficient means of transportation…
I may vary what I do but I’m thinking my main one will be MoP then a toss up between WoD and Cata. Hey I like the WoD zones . Who knows I may do an alt in revamped Van zones and Outland but I will be avoiding Legion and BfA (especially BfA ) like a bad case of herpes.
Hmm… this one is actually trickier than it seems.
Probably for the most memorable? Probably WotLK fits the bill. It’s definitely the “biggest jump” in terms of overall quality relative to the previous expansion (Vanilla and TBC weren’t really much to look at, but you were used to the structure after so long). We have several memorable events like all the run-ins with the Lich King, both inside and outside dungeons. Storylines finally became compelling, and we had tour-de-force moments like the Wrathgate and the subsequent Siege of the Undercity scenario (sadly removed for quite a while now). The Stormpeaks also had amazing moments like the Drakkensyrd (hopping from proto-drake to proto-drake), all the mysteries surrounding Ulduar… and again, the Lich King serves as a unifying force for all of it. We also have technical improvements like phasing and group scenarios (Assault on Light’s Hope in the DK starter zone and Siege of the Undercity), which pre-dated actual scenario instances and solo scenarios. It was a MASSIVE improvement… for the time.
Sadly, it hasn’t aged well at all… and one of the best parts was removed (Siege of the Undercity again) for some dumb reason. Nevertheless, it laid the foundation for better leveling experiences going forward… and for the time, it was some of the best leveling you could experience.
In the more modern era, things are generally better. As noted above, WotLK feels too dated now even though it could still arguably be the best in terms of content… but the pacing and mechanical details really don’t mesh well with the game.
From the modern era, I’d put it towards MoP. From that point on, the quality of the leveling experience (in terms of pacing and mechanics) has pretty much plateaued; it’s all very good, but there hasn’t been any huge innovations or changes since then.
So we start looking at things like character, personality, and content… and to that end, MoP has a charm that no expansion before or since could ever hope to match. WoD tried too hard to be dark and gritty. Legion confined it’s best zone (Suramar) to the level cap, so it kind of gets ruled out on a technicality here… but even then, I’d lean slightly towards MoP. BfA, even if you ignore the MAJOR issues with the level cap content, can’t quite live up to the standards set by the previous three expansions.
MoP had a heart, a fun spring in its step and knew when to take a somber tone… giving it some of the greatest highs and lows in any expansion.
BC 
Either Mists or Warlords. While I’m leaning more toward Mists, it depends on how hard the bonus XP around Warlords’ questing zones get nerf’d.
I can tell you my worst one.
It was Cata.
I was trying to get server first Mage and I missed it by 15 minutes. I was beaten by someone who was getting massive help from their guild.
I was doing it solo.
I didn’t play for a week after that, I was so exhausted and bummed. I’m glad they took server first achievements out after that.
Strangely enough, Classic. I don’t know why, I just liked it a lot more after the Cataclysm revamp.
MoP and WoD.
Beautiful zones and good storylines. I thoroughly enjoyed questing in both expansions.