The Ideal Purge Game

[Kakarat]

Character balance that lets you hit the ground running and be useful without having to spend a lot of time playing catch-up

Along the same lines as the last point, you need to be able to bring in a new player and play with them. MMORPGs are particularly bad about this. The tendency there is to say, "Hey come join us in Lord of the Worldhammer! ... Well, we're all level 90 but if you play for 2 months straight you should be able to start playing with us."

That's just ridiculous. COH/COV took the step of allowing "sidekicks" I think they called it, which at least made the game playable for newbies who wanted to join vets but I think the better solution is, again, the Planetside model, where there simply isn't a vast difference in killing power between vets and newbies. Or something like EVE, where a veteran can always beat a newbie but 3 newbies can beat most veterans and no matter how big your fleet is, there's always room and value to bring in one more newbie.

Linear games based around leveling through content will always fail at this. Even if they allow sidekicking, you're bypassing a lot of content which is a form of failure in itself.

Everquest 2 had a mechanic called mentor. Say you were level 20 and your friend was level 65. He could mentor down to your level, keeping his 65 abilities and gear. It was a fun way to level up.