Thundgot makes a point of saying this will improve performance. If you think about it, many of these statistics revolve around "best" or "top" attributes from a character's dataset. Collecting this much information for each character will take a few extra process cycles each time an attribute changes, or each time damage is doled out (since many spells / enchants / procs change these numbers). Multiply this by a few thousand times for a character in a given night (due to potential changes via combat), and then multiply it by around 11 million people playing the game... and you get the picture.
These attributes take up a lot of processing power to keep track of. And while they're fun to look at – it's obvious Blizzard has made the decision they're not worth the cost.
Hopefully in the end they're right, and this will be part of the solution in solving some of the major lag and other connectivity issues we've experienced.