It’s the same as the ancient blue troll posts about Onyxia deep breathing more each patch that players would insist on every single reset, even though the code didn’t change…
Higher CPU requirements in 10.0 and like I’ve said, along with blues now, there are some Windows/Nvidia/AMD issues going on in the mix as well. There might be some things Blizzard could do to tone back CPU thread usage, but I’m pretty sure they’d rather just wait for them to iron out whatever kinks are going on, before having to go back and refactor a ton of code. It’s going to take time to work it all out. It could be days, could be weeks, could be months. For now, the game can be played stutter free on most setups. As long as the majority of players aren’t experiencing the problem, I doubt they are going to do anything too crazy that might potentially mess things up for the majority.