Well the current speculation is that the integrated graphics with the new iCore line is really horrible. So horrible in graphic performance that the older (that is the current C2D generation) MBP would perform better than the newer (that is iCore generation) MBP. So yes, you would get a speed bump of maybe 20% and maybe less heat/longer battery life at the expense that you're new MBP has poorer graphic performance if you're stuck on just integrated graphics.
However, Nvidia's new Optima tech looks pretty good on paper. If they integrate that with the new MBP then you get the best of both worlds (increase in CPU power and increase graphics from discrete graphics while still having a long battery life) as the Optima tech allows for the usage of discrete graphics without the need to reboot.
Granted Apple could completely go in a different direction, we won't know till Apple tells us.
Given the iPad's pending release, I would venture to say it's unlikely that Apple will update the MBP till the mid summer, possibly even later than that since normally, Apple runs some sort of buy a Mac because you're going to school promotion in the early Fall. And since an iCore change is fairly significant, I don't think Apple would do one of those "silent" updates without those big announcements that we've seen in the past.
Is spending the Apple premium worth the older technology? Depends on each person, but I think a lot of folks would agree that it seems irresponsible to spend such a premium over older technology. However, as other posters have mentioned, technology is a funny thing, the next greatest thing is always around the corner. Waiting doesn't really help. Assess your current needs and wants then make a decision. It's not like Apple is going to tell you what their plans are beforehand.