The next content patch will change itemization in the Burning Crusade to make each Tier set have considerable increase of stats and socket value, to expand the gap between each tier.
The ‘cost’ of sockets on an item currently scales slightly with item quality, meaning the higher the quality an item the more a socket will account for. In an upcoming content patch though we’re standardizing the cost of sockets on high end items to match the lower end items. This in turn directly results in a base stat increase for the higher quality items, which will be seen in that same patch.
Our item designers are also going to be taking passes on all expansion raid sets and other additional changes may be seen in upcoming patches. It’s not our intention for higher tiers of raid armor to be worse or side-grades to previous sets. While in some cases they may not always have the specific stat that some may prefer the intent is that the overall item quality is indeed higher with each new raid tier.”