It honestly makes me wonder why City of heroes is the ONLY RPG in existence that ever got the idea of a leveling down or level up mechanic.
Mind you if you level down you are still powerful and if you level up you are still weak... Yet that system really worked.
Other games only level you up in PVP, but that is it.
Ohh city of heroes, I am so sad it was gone. It was that game I always intended to go back to and now I won't get the chance.
EQ2 had a level down system in PvE, though I don't recall the exact mechanics. I'm pretty sure you basically just got scaled down to the person in your group whom you choose to "mentor". You keep all the other abilities you'd have at your normal level and you probably kept some bonuses from gear. The trainee also gains bonus experience too, I believe.
Although the mechanic is nice for old players to group with their lower level friends, the problem is that PvE is kind of rote. Your older friend probably already went through all the content before, so even if he wants to help you he's still kind of put off by having to do the stuff he's done before. That actually kind of leads into a peeve of my own:
[MMO] Unvaried PvE content:
It's strange, in just a few short years MMOs have gone from having a breath of "content" available to requiring that everyone take the same path. EQ1 had tons of content - although I grant that it was all pretty much the same, and with how they tuned experience, old content was always less efficient to level in so no one went there. But it was there if you want a change, even if the only change was killing giants instead of dragons or sarnaks instead of undead or something. This got better with the next generation of MMO where they actually tried to tell a story, even if the exact mechanics boiled down to kill things or fetch things or whatever, and beyond that most people just skipped it. But there was variety, in enemies and zones, so you didn't have level up through the same thing if you didn't want to. However, as WoW aged, they focused that down - everyone had to, more or less, go through all the same content. There was some differences between the factions but even this overlapped in some cases. I guess it saves money, but why not give players more choice, especially in the leveling game? Don't require that players play through
everything to level up that next character.