Software doesn't always fix a hardware problem. If apple slapped a big ol blob of tim than yeah the heat transfer will be poor. Sure the cpu is "safe" at 90+ but the fan noise is unbearable with a small fan at 6000rpm. And yeah older mbas are hotter
Why don't you go ahead and check out the differences on the CPU and GPU since 10.6, 10.6.1, 10.6.3, and low level API access to h.264 for third party application developers... I think the facts will surprise you. And it's getting better and better. It is obvious that Apple is trying to get back in the game against Windows when it comes to the graphical media experience.