What I think Blizzard should do, regarding legacy servers.
Announce two new "Progression" realms (one or more, depending on expected load). These servers should be segregated from the rest of the content on an account - no shared pets, mounts, heirlooms, cross-realm mail, or other unlocks. All toons are starting from scratch.
One of these realms will be Serious Progression, with all the modern conveniences of life removed. No more group/dungeon finder, dungeon journals, etc. The other will be Casual Progression, with those conveniences. Anyone who wants to relive the past can choose their level of comfort. Trying to work through a dungeon tier in 1/3 the time people actually got is enough pressure, I'd think.
Both of these realms will launch on the same date (for our example, Jan 1), containing only WoW 1.0 world data (zones + dungeons, so up to BRD/MC). After launch, the server will roll through one PvE content patch every month. Patches with just world bosses or non-dungeon events will be rolled into the previous patch (so Dragons of Nightmare + Abyssal High Council from 1.8 will come in with Zul'Gurub and 1.7). PvP content will be available on a similar rolling basis, but dedicated PvP patches will be rolled up with a PvE patch, so Warsong Gulch + Alterac Valley (1.5) will show up with Dire Maul in patch 1.3.
Since new expansions typically offer up a pre-patch experience and a wider selection of max-level content at launch, I would adjust the schedule to give expansion releases two months before the next patch drop, with the first one-two weeks of that for prepatch content (Dark Portal Opens, Second Scourge Invasion, etc). Giving players an extra month with initial content should also help with the longer 1-60 grind compared to 60-70 etc.
This gives a rough schedule based on http://wowwiki.wikia.com/wiki/Timeline_(World_of_Warcraft):
- Jan: Launch, dungeons up to Blackrock Depths/Molten Core
- Mar: 1.2, Maraudon
- Apr: 1.3-1.5, Dire Maul, Warsong Gulch, Alterac Valley
- May: 1.6, Blackwing Lair
- Jun: 1.7-1.8, Zul'Gurub, Arathi Basin, World Bosses
- Jul: 1.9, Ahn'Qiraj
- Aug: 1.11, Naxxramas
- Sep: 2.0, Dark Portal Opens, Burning Crusade, Blood Elves, Draenei
- Nov: 2.1 Black Temple
- Dec: 2.3 Zul'Aman
- Jan: 2.4 Quel'Danas, Magister's Terrace, Sunwell Plateau
- Feb: 3.0 Naxx/Dalaran removed, Second Scourge Invasion, Wrath of the Lich King, Death Knight class
- Mar: 3.1 Ulduar, Argent Tournament
- Apr: 3.2 Koralon, Onyxia's Lair rework
- May: 3.3 Frozen Halls, Icecrown Citadel (opens one wing/week)
- Jun: 4.0 Cataclysm, Goblins, Worgen
- Aug: 4.1 Zul'Aman, Zul'Gurub
- Sep: 4.2 Firelands
- Oct: 4.3 End Time, Well of Eternity, Hour of Twilight, Dragon Soul
- Nov: 5.0 Mists of Pandaria, Pandaren, Monk class
- Jan: 5.2 Throne of Thunder
- Feb: 5.3 Deepwind Gorge, more scenarios
- Mar: 5.4 Siege of Orgrimmar
- Apr: 6.0 Warlords of Draenor
- Jun: Blackrock Foundry
- Jul: Hellfire Citadel
- Aug: 7.0 Legion
(Side note: Vanilla is 7 content drops, all expansions are 4 content drops except Warlords, which is only 3)
This gives a 2.5 year cycle to catch up to mainline plot. Once a Progression realm catches up, it converts to a standard realm. Blizzard should offer either free or heavily-discounted server transfers at any time for a progression character to transfer to a standard server. When either of these events occur, the player's account will receive any account-wide unlocks that the character had (pets, transmog, mounts, whatever).
A new Progression server could launch every 3-6 months, so that there's a constant rollover for those who really only liked the vanilla stuff. Alternately, some progression realms could be designated for a specific patch, and have a slower rollout of content (maybe over a year for vanilla, or 6mo for the lighter expansions).
Things I am not suggesting be recreated, in all of this:
- PvP rewards, rankings, etc as they were at that point in history
- Class skills/talents - we should just use them as they are, but if some need a rebalance that balance change should apply to live servers as well. Heavy PvP players would probably disagree, as the roll of skill revamps changes the PvP meta over time.
- Pre-Cata terrain - IMO the purpose of progression servers is/should be the sense of community that comes from no cross-realm interaction, and gear progression in dungeons (plus PvP for those that want it). Slavishly recreating old zones doesn't really help that purpose much (I wouldn't be too put out if for instance Azshara was the newbie zone it currently is instead of the high-level zone it was originally, even with no player Goblins until Cata launch).
- Original restrictions on race/class combos. Because really, meh.