Paul said in a different thread that he likes the idea of Steam and would like to. The only possible issue is the mod store Paul wants to have, which would need to be separate from Steam.
Mod Store? They already have something like that. Steam has a system(I forget it's name) where you can 'Subscribe' to a mod or texturepack or whatever, and it will automatically download/update and run! All you have to do from there is play the game!
The Mythruna mod store will be a place where YOU (the players) can upload your mods. If you choose to sell them for a fee then you can piggy back on the authentication and download/update system that will already be built into Mythruna. So, players can go to Mythruna.com, click-buy their mods, and have them show up auto-installed into their game the next time they run. Furthermore, servers will tell clients what mods they require and can potentially auto-enable them and so on. The point is to make it as seamless as possible.
The hope is that eventually the store's cut of community driven DLC will help fund the game when regular game purchases slow down. It's kind of the cornerstone of my long term strategy and I'm not sure it's compatible with letting someone else take all of the fees.
I may look into selling the client on Steam but it would somehow still have to come back to accounts on Mythruna.com.
And anyway, this is all kind of putting the cart a few miles ahead of the horse.