- Most of complex mods aren't made from scratch, they're heavily based off many other people's work, some free games assets and usually even illegally extracted assets from other games. Nobody care about that when it's not commercial activity, but for paid product issue with licensing is huge.
- Same issue with other copyrighted stuff that isn't game assets: trademark, fictional universes, etc. Currently there is a lot of freedom and you can do whatever you want, but once there going to be any money copyright holders include the worst ones going to put huge pressure on community. So mods based off books, movies, series going to end up with DMCA takedown notice really fast.
- % that belong to platform owner and game publisher is abysmal especially considering that some mods is hardly derivative work. So modder who crafter own everything (3D models, textures, animations) still going to give same cut as someone who just reused game assets.
- There is huge issues with quality and support. Even now there is issues with broken games on Steam and I have no idea how Valve can handle that. What worse modders can't fix some bugs on their own and there is many cases when game developers just don't care.
And that all not include fact that weird monetization model going to demotivate many tool and content creators. Not every game is suitable to sell hats.
> I'd like to see Valve take another shot at baking mod monetization into the Steam platform.
I would be more happy to see platforms like Patreon become more popular. Support modders or teams directly is much better idea than selling mods. As example here is one of OpenMW developers:https://www.patreon.com/scrawl
It's not huge amount of money, but OpenMW isn't most popular project around. This isn't really "mod" too, but I remember I seen few Minecraft mod creators there as well.
Try and monetise mods, and you pretty much kill this part of the hobby all together.
"Just add a tip jar", the first comment reads. Right, mate. You can head over to Wikipedia right now to see how hard it is to get people to give you money:
http://i.imgur.com/rOyVz43.png
I'd like to see Valve take another shot at baking mod monetization into the Steam platform.