Hi Dennis,
I shoot fashion and as we all know this lens is stellar, very heavy and very expensive. Are you shooting fashion for fun or professionally...?
Personally I don't think it's a fashion photographers first choice lens, in fact I don't know many that use it a lot, if at all. If we want that long lens 'pulled in' look, we hire a 300mm 2.8 and be done with it. for beauty a macro lens is often used, the 105's or the Sigma 150mm, these let you compress perspective a bit and allow you to go in close without cropping the file afterwards
The 200mm f2 is killer sharp and for beauty it's perhaps too sharp, most clients/editors/CD's etc are not bothered about the difference between your 70-200 2.8 at 200mm compared to the 200mm f2.
They are looking at the styling of the shoot, model choice, product info, quality of the hair and make up etc.... Don't get me wrong, a lot of creatives are keen snappers and appreciate quality but we are comparing high quality lenses and beyond a certain point the contents of your shoot are more important that what you shot it on.
In a nutshell, buying this lens will not further your career one jot, investing the money in shooting fresh work for your book, on location, with high quality models, a decent (expensive) stylist and hair and make up team will get you much further.
You already have 'industry standard' high end lenses in the two you mentioned, you don't need anything else, 'cept maybe for the 50mm 1.4/1.8
Steve