The biggest noise related to the expansion ("Inferno") that arrived a couple days ago is related to the new inventory system. The forums are filled with angst and CCP has a plan to fix some of the major inconveniences.
Personally, the new inventory system seems fine. I can still do my usual shuffling of items and building of ships. No big deal.
But apparently it is a big deal to a small group of Eve players - botters. Their botting programs aren't working and the new inventory system is causing havoc with them. It seems possible that this is a side reason for CCP's changes to the inventory system since it's no doubt a main part of any botting software.
Check out The Nosy Gamer for a fun read on the subject (he's often writing about botter tears...). http://nosygamer.blogspot.com.au/