Well that hasn't been my experience, so we'll just have to agree to disagree. The minute I started working in Lightroom and Photoshop or watching YouTube on my rMBP, it would completely overheat, reaching temperatures sometimes up to 200 degrees (and this was while keeping it on a pad, not on a bed or my lap). To me, that was not the "best cooling". I wouldn't mind if the MacBook Pro got thicker but had better cooling. I know cooling is not a priority for most because they probably don't do tasks like that on their laptop, but some laptops are capable of it without getting so hot and it'd be nice if the MBP was too. I use my computer in all different places, so an iMac isn't really a good option for me.
At this point I'm just hoping the MacBook Pro doesn't sacrifice power. Get it thinner, hotter, whatever, but if the power options are the same then that will be fine with me.
I'm going to be buying it either way...so...kinda just noise from me at this point.