dclivejazz

if you shoot concerts or acts on stage at less than 1/125s I'd imagine the motion blur is present on almost every photo, if that is the look you're going for that's your artist interpretation.
When i shoot events I'd much rather have a usable high ISO, than be able to slow the shutter speed, as I generally do not want motion blur on the acts i'm photographing. (the exception being if I want to show movement)
 
All IBIS or OIS does is allow you to use a slower shutter speed, on long lenses > 100mm it is an advantage being able to use a shutter speed of 1/60 seconds without camera shake.
 
But shooting a 50mm/35mm lens (or wider) it makes no difference, as less than 1/60s motion blur will appear on anything that moves, and shooting a 35mm lens at 1/60s or faster there is no camera shake.
 
I also do plenty of candid street photography, again never missed a shot because of no ibis, as I'd never be using a shutter speed so slow camera shake became an issue before motion blur did

This probably has a lot more todo with future Video features than photography, maybe the new Super X mount camera that was rumoured.
 
In photography IBIS has limited usefulness (same as OIS on <100mm lens), being able to hand hold a shot at 1/4 second using a 35mm lens is of little use unless your subject is stationary
You may not have camera shake but you replace that with motion blur.
 
I honestly can't think of a usage for IBIS for photography, that the 16-50, 18-55, or 18-135 lens can not do with their OIS
Architecture or landscape shots at night without a tripod, since you are using F8/11/16/22 to get the required DOF all those can be done with lens with OIS that are available now.
 
Don't get me wrong for handheld video it will be great, but for photography I can not see the point other than a tick box item

I have the 35 and 23 f1.4, both of which are terrific lenses. However, my favorite in rendering, contrast, color, sharpness is still the 16 f1.4. I can see how the variances in the lenses may make one person prefer one over the other. It's all good. But I am really enamored by what the 16mm produces.

I use a very simplified approach to this whole comparison question:
For focal length comparison, find the crop multiplier and find the lenses that have the same field of view after applying that multiplier. For example, 50mm on a Canon 5D MkIII, 35mm on a Fuji X-T1, 25mm on an M4/3 camera.  For light gathering, take the f-stop and be done with it. Exposure setting should be the same when using f/1.4 on M4/3, APS-C or FF.  For depth of field, add one stop for each sensor size doubling, that would mean f/1.4 on M4/3 is similar to f/2 on APS-C which is similar to f/2.8 on FF. This isn't exact though, but it's close enough to be workable.  So, it's true that for DoF and rendering comparison the 56 f/1.2 should be compared to an 85 f/1.8 on a FF body, but that doesn't apply to light gathering. But because a lot of FF sensors have better ISO performance than a lot of APS-C sensors, you could argue that you can just use one stop higher ISO on the FF camera and still get equivalent results. 

It would be close with only the difference between the way a 56mm and 85mm renders an image.
 
If you take in the perceived DoF between the two systems you want one stop larger aperture on the crop system to get as narrow a depth of field or one stop smaller on a full frame system to achieve as much DoF.

Black Pearl's explanation is perfectly correct but may also confuse a little bit as it mentions "full frame lens".
All 56mm lenses have a deeper depth of field than 85mm lenses. It does not matter if the lens is made for full frame, APS-C or MF4/3 or any other format.
(Or more general longer focal length give less depth of field and vice versa.) And lower aperture numbers also give less depth of field.
 
For a typical portrait lens you would choose 85mm on a full frame but 56 on a APS-C. They will give the same field of view but at a given aperture the depth of field is different, shallower on the 85mm. You can compensate this by a lower aperture number on the 56mm i.e. 1.2 on the 56 instead of 1.8 on the 85. If you want to compete with with your Fuji with an 85/1.2 on a full frame you are screwed. You would need a 56.6/.80. To the best of my knowledge there is no  such lens.
 
But Bokeh is just one side of taking pictures. Sometimes I would prefer more depth of field for example often for documentary and street photography. In this case I can open my aperture by one half stop to get a faster shutter speed for less motion blurr but still get the some depth of field as on a full frame.
 
Exposure wise a 1.2 lens is a 1.2 lens regardless on what format it is used and for what format it is made.(Of course, some lenses have a better transition than others. This is the reason why cinematographers are using t-stop rather than f-stops, as Balck Perl has explained.

An f stop is an f stop is an f stop - well in photographic exposure terms it is where the infinitesimally small differences in light transmission due to the glass don't matter in the same way they do in the movie world where they have lenses marked in t stops which are corrected a little further.
 
Essentially the person you're quoting is wrong, or at least is interpreting things the wrong way.
It is very easy to test if you have a Nikon and a few lenses. Put a FX lens on a Nikon FX body and take a shot at (for example) f2.8 then swap it out for a DX lens and set that to f2.8 - the exposure will be the same. You can actually use some DX lenses on FX bodies and get a full frame exposed. The AF-S 35mm f1.8 G DX can just about do this once its stopped down a little and many zooms do the same as you alter the focal length- the Sigma 10-20mm from memory is full frame from about 16mm.
 
I think what the person in the quoted article is misunderstanding is the apparent difference in depth of field between the two systems for a given aperture. If you stood in one spot with a FX body and a 85mm f1.4 and took a picture at f1.4 then did the same with a crop sensor camera using a 56mm f1.2 set to f1.4 you would get about one stop extra depth of field - the exposure would be the same. By opening the 56mm up to f1.2 you would then get a picture with a similar DoF to the 85mm.