Assuming it's a console that is somewhat better than the PS4/XB1 in some areas, but still in the same ball park ...
Even if it launches this November, that means the PS4 will have a headstart close to 45+ million and XB1 will be around 25-30 million.
Worse if it launches in 2017, the gap probably grows to 60+ million for the PS4 and XBox One 30-35+ million.
Wouldn't it pretty much just be destined to be a third place console? Never in the history of game sales has a platform come from 30+ million down to catch up.
It would also be at a huge disadvantage in terms of game library (both systems will have thousands of games by then) and because the PS4/XB1 have the install base they have more users in their online infastructure so this creates a snowball effect for them (ie: I want to buy a next-gen console, 2-3 of my friends already have a PS4 ... I'm more likely to choose a PS4 so I can play with them). And PS4/XB1 will likely be at least $50-$100 cheaper than they are now.