I have a feeling that the new XTrans II sensor is going to be a game changer.
The fact that the have on-chip phase AF is going to radically change things in the AF speed department.
They are also adding a new processor chip, claiming a big improvement in IQ over the original sensor.http://www.fujifilm.com/products/digital_cameras/x/fujifilm_x100s/features/page_02.html
Add these facts together + the first RAW convertors showing up like CaptureOne and we are going to have the best FF IQ (like D800E) from a smaller, cheaper camera.
I can already get sharper images out of my X-Pro1 or XE-1 + the 35mm F/1.4 than any lens I've tried on my 5D MK3 and I have the new 24-70 F/2.8 II and and a 70-200 F/2.8 II and returned a Sigma 35 F/1.4 and have tried a host of others including Zeiss.
Oh yeah and adding focus peaking is the icing for manual focusing of old lenses.
There's a bit of magic you get from old Range Finder lenses that is sadly lacking from the modern DSLR
I have my preorder in for the X100s and I'll sell my X-Pro 1 and wait for the X-Pro 2 announcement in September...