MMORPG Theory Question

[Doppler]

I was debating somethings about MMORPGs the other day. In my mind the make or break points for a good MMORPG are always going to be the following.

PVP
Crime
Balance
Niches
Diversity
Economy

PVP:To have it or not is the biggest question you can ask when doing up a PVP. A pvp that starts without it, and then adds it later can be so horribly screwerd up.

Crime:Whether you have PVP or not crime is a major issue for any MMORPG. If your in a multifaction system where ganking any ships/guards/shops etc is ok as long as you dont expect a warm reception in their systems great, but if you want to live totaly above the law and prey on everybody your choices of safe resting spots should be severly restricted.

Balance:No class/combo/build should be siginifigantly less usefull then any other.

Niches:The flip side of balance, every class/build/whatever should have a few things it does better then anybody else. The problem here is limiting things that are good in groups but worthless without one, or awesome to solo but never can find a group.

Diversity:Take a look at City of Heroes, theres enough diversity there to keep everyone happy, even among the same class. Try and avoid "Random Half Elven Ranger 0000002"

Economy: Economy is another hard thing to balance, you want currency to have value, yet is easy enough for new players to get good gear for their level that they dont become disenfranchised. In my mind limiting gear by level seems about the best solution.

Thoughts?