Well, you're right, it seems that the only chance people have to hack a mmorpg is hack the server, but that require a good knowledge of programming...and i think that work with many mmorpg.
But my case is a little different, 'cause it's a flash game, and i have found the main file with all the actionscript, well...most part of it. I've ever done some changes that works, but it was only "graphics" changes. Now i want to edit the script contained in the main .Swf file, but it's a little more difficult than i tought. This swf file is more complicated to decompile than i expected...;-)