So, who's the target audience ?
Gamers play on their computers, they also want to use them for other things. So not them
Console gamers, to expensive, not standardized and the vast majority would build/buy a system to install an OS on to save their lives. Leaving the steambox OEM possibility for them, 800 dollar steambox or less than 500 dollar Xbox one that also has access to Xbox music and movies, spotify music while playing games, kinect and so on...
Not saying it'll fail, but I don't see it being a success.
The way I see, I think it will be aimed at people in the market for a console who are already heavily invested in PC gaming, and not looking to spend £50 a time one games. The OS itself has the advantage of being separate from the hardware, meaning that one could repurpose an older PC, or optionally build their own. It also allows the possibility that 3rd party Steam boxes could be created. Like I said before, it's also got 200 launch titles (that we know of), so there's that too. Apps-wise, SteamOS could be lacking, but then we've not been told much on that front so it could change.
Gaming OS? It will most likely only play Steam games. That means any game from Origin or games you have to install outside of Steam WILL NOT work. You won't be playing BF3, BF4 or Titanfall (when it ships) on SteamOS or SteamBox.
I don't think you're going to see the Steambox with ps4 or xboxone quality of hardware. For that thing to be successful the price will have to be 100-299 dollars.
The reason why a lot of people are dumping on it is because it's pointless when you have linux distros (and windows) that already have Steam and play just fine.
So by that logic, the Xbox One isn't a "gaming console" because I can't play ARMA III on it. I agree that there won't be as many AAA titles for Steam OS as for the consoles, but then again, let's wait and see .
Hardware-wise, we know nothing but guesses, so we'll have to wait for another 43 hours to see what they announce next.
I disagree that having a separate Steam OS is pointless. One of the things that drives games development away from Linux (aside the small market share) is the abundance of different distros. Giving everyone a single, well supported and specialized distro to get behind will be beneficial to Linux as a whole, especially if Valve pump their changes upstream when possible. My only hope is that SteamOS won't be TOO specialized and end up making it so that games written for SteamOS won't work on other distros.
Like I said, we have exactly a third of a picture, and we'll likely be waiting until the end of the week before we know the full story. That was my point!