Well my 2011 17" finally died so I bit the bullet and got a 2017 15". It's so nice being so small and light, and although the screen seems small to me, you can now buy portable screens (Asus Zen screen) which is about the same size as the 15", probably brings the bulk and weight back to 2011 levels but then you have 2 screens! Obviously not of interest to the café warrior or train worker, but for us freelance designers who literally need a portable desktop replacement, it could be the ultimate solution. I'm going to hang fire and see how I get on, and maybe wait for more such screens to enter the market, but it is an interesting development for mobile designers - 2× 15" is going to be better than 1 x 17"
Of course the screen quality won't be as good on the 2nd screen but I can put my text doc, or emails, or Adobe app palettes on it and have more screen space for the image or doc I am working on on the MBP. Maybe I don't care any more about the lack of a 17" model.
I still would've bought one if they'd had one in this year's line up though!