Imagine WoW without levels

In yesterday's discussion of end game option I mentioned that MMORPG games are scaleable. And several commenters mentioned that they would prefer games without levels. So I was thinking how to combine these facts and make levels in WoW irrelevant and came up with several different solutions. Imagine the following hypothetical World of Warcrafts:

A) All instances would scale the difficulty of their monsters and all the rewards according to the level of the group entering the dungeon. If a level 70 group entered the Deadmines, the mobs would be level 70, and there would be level 70 blue items dropping. If a level 20 raid group entered Karazhan, the mobs would level 20ish. The bosses would drop purple epics, but they would be level 20 epics, barely better than level 20 blue gear. Thus dungeons would never become irrelevant. If you liked Gnomeregan, you could go there with your friends at whatever level you are, and always get rewards appropriate to your level.

B) The dungeons of World of Warcraft would remain at the level where they are. But whenever a group enters the dungeon, all group members are set to the standard level of the dungeon, regardless of their previous level. So a level 20 could group with a level 70 and other characters of whatever level, and when they enter the cathedral part of Scarlet Monastery, they would all be level 42. Their gear would likewise be scaled up or down to level 42. The monsters would drop whatever item they usually drop, for example Whitemane's Chapeau from High Inquisitor Whitemane. In the instance everybody would see the normal stats of that item (Cloth head armor, 52 Armor, +14 Spirit, +14 Intellect, +9 Stamina). But once out of the dungeon, the chapeau adjusts to the real level of the user at the time he entered the dungeon. Thus it would always remain a head cloth armor with bonuses to spirit, intellect, and stamina; but for a level 20 it would give less of those than normal, and for a level 70 it would give more.

C) The most radical solution would be to forget about levels altogether. Every character on creation starts in a single-player instance, or even offline like in Age of Conan. In this instance he levels up to 70 in a few hours, learning all the spells and abilities of his class. Once he enters the multiplayer part of the World of Warcraft, all the monsters he sees are level 70, all zones are level 70, as well as all dungeons. With everything at the same level, basically there are no levels any more.

I don't think that any of these hypothetical WoW's would work much better than the current one. It solves some problems of content becoming obsolete, or people not able to play with each other. But it creates bigger problems with a loss of motivation. Leveling up and character development are major driving forces of MMORPGs, if you take them away many people just won't be interested any more in playing. If anything would work, then probably a more individual system of mentoring / sidekicks like in Everquest 2 or City of Heroes, with people being able to adjust their level to that of a friend to play together. But I don't see that used all that often in EQ2, because the rewards don't scale.