I agree that currently, everyone who needs a dedicated GPU is going to get the MBP. Obviously.
But I am willing to bet the vast majority of current MBP customers doesn't need the GPU. You don't need it unless you are a gfx professional, or a gamer. If you are a gamer, chances are you have a gaming PC laptop as there's way more games and way more hardware options.
Lots of stuff in OS X is hardware accelerated with OpenGL - but for that, the integrated graphics are plenty fast, even if they suck as much as the Intel ones.
Think about what you just said. For the first sentence, I agree. That's obvious. If they need a laptop with a discrete GPU, they'll get the MBP.
For the second, you're right; a large percent do not need the discrete. Now your logic or reasons WHY that might be the case is flawed. If I'm a gamer, chances are I have a gaming PC? Really? Now you're just trying to pad your argument.
I don't know how speed relates to anything in this sense. On a basic point its about memory. It's integrated and doesn't provide near enough power for any "real" gaming at all. People get decent quality/framerates on medium settings but with the newer games coming out (Skyrim, BattleField 3, even MW2) you need something better.
You really expect someone to already have a gaming rig then get a MBP? Let's be serious here.
What you're saying doesn't make sense.
So for all these people that don't need a GPU, Apple currently doesn't offer a machine larger than 13". It makes sense to have a 15" option. I know Apple likes to keep their lines clean but I am hoping they will offer both a MBA 15 and a MBP 15 to please everyone.
I'll opt for the Air, most likely. The GPU is no help for my work, and it wastes battery and produces heat. It's turned off on my current MBP, and I would turn it off were I to get a new MBP too (I don't trust automated switching, particularly when I really don't have a need for the GPU at all).
PS: Is the GPU really that useful for Photoshop? Does it actually take advantage of a faster GPU vs the integrated graphics? I don't know as I only use PS occasionally and not for anything requiring any CPU horsepower.
This is true. However, it seems that you're missing the point of it ALREADY being here. It isn't like there are only MBPs 13-17 that do NOT have the GPU, they already do (15/17). Having a 15 inch Air.... seee it doesn't make sense.
You have 2 notebooks. Air for the average, Pro for the person who does intensive work. That's great. Now they can add the 15 inch air and beef it up but KEEP the current Pro line (and they really are going to beef up the next Pro line, all of the models) and that would make the most sense, for me anyway.
11/13/15 Air for the average and a more expensive Pro at 13/15/17 inches. Or they might even get rid of the 13 Pro... but I dont' see that happening.
There are a lot of possibilities but your aforementioned argument doesn't really make sense.
If they release a new, larger Air, I'm really, really betting it would have a discrete graphics chip, the same as the one in the 15 pro baseline. Of course, the 15 air could look different; think the MBP body but thinner. Like a very skinny rectangle; a lot of people tend to think of a teardrop design and that just doesn't look right with a 15 inch laptop, I don't think it would anyway.
They could thin it down, give it a dual core with a higher clock speed, no dvd drive, and a 256 meg discrete graphics card.
PS: But for the PS, yes it does make a difference. Depending on the level of sophistication for your work, it will make a difference. For the person who's just applying saturation, contrast, blur, or other basic levels over a picture, you might not need it. However for those doing much more intensive work in Photoshop or whatever, they have better results.
The iPhone 4 has a gpu in it and you can plainly see how polished and clean everything looks. It has a better SDK than Android's and the polish, shine, power, and speed of the entire iOS and its applications shows. That's all due to the help of the GPU.