I think power leveling is a play style. Power leveling does not mean you are using illegal exploits. It's like when the media got a hold of the word "hacker" and ruined it. Maybe the story is more important to one person, while getting the next level by killing 173 super one armed radio-active monkey's is another. I hear a lot of people say "I worked for my levels...you should have to too". I just laugh when I hear this. For anyone who thinks they are WORKING when they play a mmp...hell, I don't know. Game / Work... don't they contradict each other? Anyway if I were able to make one design decision for a mmp I would do this: After you level one character to max level you get double xp for all alts on 'said' server. What would be the problem with that? I would think it would *help* with people who try to find any means necessary to earn the most xp/hour. And by "any means necessary" I mean using illegal exploits.
