I agree that the perfect legibility for a chronograph would rather demand a central minute counter hand than a small subidal. But I think if there is only the latter, it should at least be possible to use a chronograph in a manner it was designed for: to take an accurate reading of elapsed time.
I admit, though, that sometimes a nice design gets priority:
This is my AquaTerra chronograph, and I really like it for its nice proportions and elegant design. Apparently, its designers wanted to make a chronograph that keeps the subtleness of a three-hands-watch, while offering the possibility of a chronograph. Therefore, the three subdials received only a minimum of markers, to the effect, that at first sight the subdials are not conspicious at all. However, this is exactly the "feature" that puts me off a bit. Although, in the Omega's case, there at least are subdivisions of 2.5 minutes on the minute counter (regardless of the fact, that the minute counter hand is jumping every full minute, and therefore never can meet these 2.5 minutes markers), permitting an accurate reading - albeit after a while of concentrated staring and calculating. The Corum, however, is even more reduced, and I think this takes the design too far, since it does not only dominate the function, but renders it unfunctional altogether.
Regards,
Marcus