[How do I select Steam or GoG?]

You do realise that whatever hosting platform they chose would be physically executed by a third party company, just like hosting with Steam or GoG? Except that unlike Steam or GoG it would cost a lot more to implement and would likely be less reliable in the long term?

 

Just sayin'.

[If Obsidian + Kickstarter = ?]

Following from other comments, without wanting t obe too prescriptive, I'd suggest an innovative setting. Possibly something ostensibly shiny-shiny. But with a flawed protagonist. A screwup with obvious weaknesses, sometimes en-nobled by better intensions or scruples. Surrounded by hordes of staggeringly well-crafted characters.

 

Criminal investigation would be cool. But it's a tricky one to do well. i.e. make it so you can draw the wrong conclusions and follow dead ends and get the wrong fellah sent to the dragon chair.

 

The dragon chair is like an electric chair except it's more flamey, and it's got wheels.