We'll see. I think Crysis 3 will run just fine on a PS4/720.
If you want to pluck down for a 4TFLOP GPU w/4GB GDDR5 RAM + a main CPU w/8-16GB of additional DDR3, for what will probably amount to a barely visible difference in graphics ... go right ahead, lol.
Crysis 2 wasn't even that big of a seller, if they want to make a game that costs $100 million dollars, they might as well start filing their bankruptcy papers while they're making the game.
The original Crysis on PC sold about 680,000 copies for example ... this just isn't enough sized of a market for 99% of developers to bother going beyond 720/PS4 which is likely to already be an extreme level of visual fidelty and raw processing power.