Steam currently has a distinct lack of isometric tactical-ish MMORPGs available at the moment, you'll be happy to know that Wakfu is heading to the platform on September 18th. The game is currently in closed testing until September 16th, with no character wipes planned between now and the launch.
Closed beta players will receive a special reward in the form of an item inspired by Valve's properties. A thread has been created for the developers to share places where keys are available, for those who want to get in on the Steam testing before it's too late. If you'd rather just wait a little bit until the launch on the 18th, that works too.
[Source: Ankama press release]