I guess we interpret some things a little different. I say it is definitely significantly different. The difference is just less than I expected or had hoped for.
Also TDP is not average heat output it is supposed to be maximum heat output (Turbo doesn't count).
Also in Penryn's case the heat dropped a lot. Just search for the wolfdale stock cooler. That thing was tiny and almost like a third of the former in size. Heat decreased by a big amount. TDP was simply rated the same because that is how Intel like it. Heat reduction wasn't big enough to move chips into a lower TDP class especially at the beginning of production with a none mature process and still a little higher V. Yet only a fool would claim that the T9000 and 8000 series wasn't a lot cooler than the T7000. Half a year later there were the P9000 series that came with 25W TDP.
Power consumption and heat was always very closely related.
TDP is just an very very basic approximation. Some CPUs are simply in a higher TDP class because they don't want them to look to good. There are loads of low end CPUs that would deserve much lower tdp classes.
Maximum heat output is pretty questionable, because like you said, Turbo factors in.
But that's the problem. Whether you want to include it or not, you can't disable Turbo. At least not on a MacBook running Mac OSX. So it is always factored in for mobile, and thus TDP for mobile becomes more like an average figure than a maximum figure.
In fact, we should look at Core i processors with Turbo and use them as the base rather than talk about Penryn... because obviously Ivy Bridge isn't Penryn.
The new one of course. It's not really a problem!
Right now it's the same situation between the early 2011 and the late 2011 models. The Ivy update might actually bring other new features (redesign? retina? 7XXX series ATI GPUs?), so it's really a no brainer.
In case it's just the same enclosure but with a new ATI GPU and a new Ivy Bridge CPU, which would be your choice? Pay $500 difference for 10% improvement in performance only?
While I am not completely of the belief that Retina Displays on Macs are impossible, I sincerely don't think they are ready for this year yet, or drums would have sounded, part leaks would have flown all over the place, and more assets would have been put into Mountain Lion. I believe Retina Displays are more for 2013... when Apple has stabilized the display supply channel for future iPads and they can wholeheartedly go back and apply the same principles to Mac screens.
The redesign rumors are more likely, but again, I'm not sure we'll see it this year. Intel is still delaying Ivy, and without chips to design boards for, I don't think Apple can complete a redesign any time soon. At this rate, it'll be August/September until we can at least see any new Ivy chip, but that's mostly because Intel pushed Ivy release dates back.