worst. reasoning. ever.
Every update is going to get you more for the same money (or, with radical changes, a LOT more for slightly more money). By your reasoning, apple could have bumped the hard drive capacity on each model by 20 GB, changed nothing else, and people should still happy with it at the same price.
If there were new models every 2 weeks, going a bit at a time like that would be fine. But as of now, updates only happen once every 6, or 8, or here, 10 months. So when they do occur, they better be significant because it's the model we have for a nice long while.
Basically, you assume that the old MBP was a good (or at least OK) buy, and that therefore any additions today are gravy. But it wasn't a good buy. When it first came out, it was competitive in terms of price and power. But it's been unchanged (except for the tiny processor shift in May) for 10 months. Until today, the MBP was very close in specs to the macbook with no real advantages besides 2.1" and a dedicated GPU, yet it cost a great deal more. It also lagged badly behind PC laptops in terms of both specs and price.
So IMO, today's update got the MBP competitive again. The fact that you can't go higher than an x1600 is a major flaw for many people, but other than that it's awfully good. But keep in mind that this is the MBP we're probably going to have for many more months. So don't just ask whether it's good today, but whether it's good enough to be competitive for another 6, 8, or 10 months.