What a bizarre thing to say. I can't think of any of the newer mkII lenses which have worse out of focus rendering than the mk I versions. 24mm f1.4L mkII comes to mind. All of the big white tele zooms. The 70-200 f2.8 II LIS is another example, in fact it's only slightly better than the mk I.
The 135mm f2.0 L's bokeh is pretty bad when stopped down due to uneven or non-rounded aperture blades. Drop to f2.8 or f4 and see the Bokeh shape....pretty mis-shapen
I was not talking about Canon only, I had Sigma (35) in mind, as well. Oh, and Zeiss, I agree with the poster above. And the 70-200 II has worse bokeh than the I, and they both seem to have worse bokeh than the non IS.
Who in their right mind would stop the 135 down? I have to try it some day... Anyway, this is not a question of lack of optical modern design, which was the point of my remark.