there are too many items which you can just casually buy with 2m, and they have such big use for it, such as dragonfire shields, while in runescape they're worth a fortune, here you can work your ass off for 10 mins and get one, doesn't seem fair. perfect way to salve this is get more item sinks i guess, i've debated with charr once about dragonstone armor being implemented which would require dragon visages to upgrade to higher tiers, but came to the conclusion it was too soon for this server.
other huge downside of the economy is that whenever a new boss or item gets introduced into the game, it gets milked so hard that it crashes instantly, a perfect example would be staff of lights, all the saradomin boss rooms were packed once it got released. sadly, there's not much to do about this flaw.
despite these two flaws above ^, it's pretty decent.