you know, i just thought of something. i think its going to be more than cooling. check this out.
1) i don't know who knows this, but the colder a chip is, its the better and more reliable it performs. so btx can make your system more stable.
2) chipmakers have to make sure that their chips don't overheat, and make sure that when an end-user buys the product that heating isn't a possible issue. so the new btx with better cooling can simply mean that it would be easier for the chipmakers to produce technology for our computers without worrying about over heating too easily.
i use chipmakers because this overheating issue isn't just a processor problem. it also affects your memory and your chipsets.