Not sure why 17" is seen as professional and smaller laptops consumer.
It isn't size that distinguishes it. In fact, there is a MacBook "Pro" model available in both 15" and 17" configuration. the 15" version is actually getting a little long in the tooth (I just sold mine and moved back to a 17"). Other than the screen/size, I believe there are only a few differences between the 2 sizes. The 17" sports 3 USB ports vs 2 on the 15", the 15" can only access 4gigs of RAM vs, the 17" which can access 8 gigs of ram, and the 17" has a larger "permanent" battery where the 15" still allows yo to carry a spare battery. The dual video cards and CPU options are the same for both sizes.
Personally I prefer the gloss screen on a portable, I feel it is viewable in many more situations and lighting conditions including brightly lit places, and I don't do any final editing on it anyway. The antiglare screen option was introduced on the 17", which was introduced many months after the original 15" version. For those that prefer the antiglare screen, hopefully they will add that option when they refresh the 15" model.