There was me thinking it was a question of space on the logic/mobo for both the pants discrete graphics chip and the 320M
Read the rest of his post
I agree with
steeex that it's in part a manufacturing problem, but I also think that the current C2D models shouldn't be underestimated, only because they have a C2D and not the hype-of-the-moment i-series CPU. For the majority of the 13" owners/buyers (and that what Apple is aiming at) the C2D has more than enough processing power, and even though it'd be really nice to say you have an i3 processor, the difference isn't all that big. Like
Apple said: "We chose killer graphics plus 10 hour battery life over a very small CPU speed increase. Users will see far more performance boost from the speedy graphics." Given the Intel/GPU problems, I think this was a good choice.
Having that said, for people who want to upgrade to a 13" and already have an older C2D it can be hard to justify buying
another C2D years after they bought their current one. This is in part a valid point, because although slower, a C2D 2.0GHz from 3+ years ago isn't that much slower than the current C2D 2.4GHz base model. On the other hand, the "i3" is getting more and more of a hype word without people actually knowing the real difference between that and the current C2Ds. And as always with Apple, there's more to its machines than a comparing a few specs. The unibody case, glass trackpad, LED screen, backlit keyboard, etc. are all worth going for the current 13" MBP.
The downside of all this is that it leaves a relatively small group of customers who want the best of the moment in the 13" enclosure, and they are simply out of luck and should either wait, go for the 15" or buy another brand.