Gabe I'm happy your here, I'm mixed on my feelings of this. I know Valve is happy to try out new methods to create revenue sources and that you tend to involve the community as a whole to distribute the burden of content creation.

However with MOD's I think you've cross the territory where you instead segment away those who can pay and those who can't. MOD's have been something inherently free to the PC community for a long time. They're free with the conditions that there are no requirements on the mod makers to keep the project running, they can drop it anytime. This is not Downloadable Content like skins, maps, or anything else you provide with your services that will be continued and supported by the developer. With Dota 2 you've made many great efforts to support older sets after remodels. If these mods will be supported by the developer and guaranteed to keep working then these transcend mods and become DLC that would be acceptable to us.

The problem is this is unreasonable, and can't be done. As such I feel that this system doesn't create any inherent long lasting value and instead creates short term capital at the cost of a consumer loyalty. Once customers are burned from a dropped mod, or a failed purchase that doesn't work after a patch this will reduce the people willing to work in this space.

You're also setting up the MOD developers to take the fall with you, which will greatly affect the future of these developers. They may have had promising talent but the backlash of this program will not be restricted to your side alone. All those who partner with you will feel the after effects. Large companies will be fine, but individual MOD developers will likely be shunned by the community forever for this.

I urge you to consider if this really has a long lasting revenue model. MOD's are not DLC and charging for them is counter intuitive for the consumers. I think the long term effects of this program are very dangerous without additional constraints or support to make this investments worth while.