It really depends on what is Nintendo objective, if they want to "steal" shares form MS and Sony catering HC gamers a custom Steam machine would be a good idea, if they want to bring back families, and casuals, it won't help much.
I also tought about a custom steam machine some weeks ago, I'll add Nintendo could let Steam developers use thier proprietary controllers, (WiiU controller, and wiimote) adding a small fee on the game price.
Anyway, this is only speculation, there is no evidence pointing that Nintendo is planning something like this.







