Did some basic math for this one after reading stuff from the Workshop FAQs.
Valve and Bethesda takes 75% which leaves the mod creator getting 25% of the revenue but you have to give Valve your tax information and according to Workshop revenue FAQ, the may take 0 to 30 percent as tax. The same FAQ says also that you must earn at least hundred dollars to actually getting the money. This seems highly favorable to the companies involved. You have to be able to sell your mod for 400 dollars to be actually paid and you may still have to pay 30 dollars as taxes from your share. So your 400 dollar sales may actually turn out to be 70 bucks. Which would be 17,5%. So depending on the taxation, creator gets only 17,5 to 25 percent.
"Introducing New Ways to Support Workshop Creators"... yes, but mainly you support big companies and that makes me a bit sad about this.
25-75 split for Steam hosting your mod. Hahaha, no. Fuck that. I'm all for content creators making something off of their content, but this is stupid.