NO, F/2.8 isn't fast enough! Not for most pros anyway...especially considering that digital cameras suffer from faster ISOs. Consider the Canon pro line up: 24/1.4L, 35,1.4L, 50.1,4, 85/1.2L, 100/2, 135/2L, 200/1.8, 300/2.8 IS, etc. Leica M: 28/2, 35/1.4, 50/1.0, 75/1.4, 90.2. Nikon: 28/1.4, 35/2, 50/1.4, 80/1.4, 100/2 DC, 135/2 DC, 180/2, ect. These lenses don't exist for nothing...they are essential to certain styles of shootiing
making use of available light...even when using flash.
In my opinion not having a 35/1.4 in an N mount is criminal. The manual version is a steller performer, so why it isn't available in a N mount escapes me. Instead we get a 400mm which is nice, but a limited use lens for a working pro.