For people familiar with Intel's Tick-Tock cadence - this should not come as much surprise. Some people may have gotten caught up in marketing and expected more, but this is a "Tick" which brings a process shrink, power savings, and a modest performance increase. It is just about delivering that, though perhaps on the softer side of things.
Sandy Bridge was a Tock - a BIG performance improvement. Haswell should be a Tock - a BIG performance improvement.
On the tick, they set more modest performance goals, and focus on getting the process shrink right and tuning things up. On the tock, they should knock our socks off. So maybe Ivy Bridge is disappointing, but perhaps familiarity with their product development strategy helps to manage expectations
Never trust an operating system.