Dear Photographers with Canon lenses - about Canon EF 70-200 f/2.8L IS USM II compared to Canon EF 70-200 f/4L IS USM?

[neuroanatomist]

Is it possible that my lens is so called "soft" one?

The 70-200mm f/2.8L IS II should be very sharp - slightly sharper than the excellent 70-200mmm f/4L IS. Assuming you're using autofocus, most likely you need to perform an AF micro adjustment on the 70-200mm f/2.L IS II (hopefully, your body has that capability!).

I read somewhere on Internet that the 4L IS USM version has one FLOURITE lens element! Is that really true? and that I could not find that the version II of the 2.8L IS USM had one?

The 70-200mm f/4L IS has one fluorite and two ultra-low dispersion (UD) elements. The 70-200mm f/2.8L IS II has one fluorite and five UD elements.