With 11 elements in 8 groups the 12mm features; Dual Super Aspherical lens, Super High Refractive lens element, new Zuiko Zero Extra-low Reflection Optical Coating, an ED lens element, and one Aspherical lens, some of the most exotic lens element combinations I’ve heard of.
All I really care about is that it focuses to within 8 inches (I love really tight wide-angle compositions) and doesn’t look like a toy. The rest is just details. I look forward to the howling on the DPReview forums about the $800 price, as if (hopefully) well-built, (hopefully) excellent, fast lenses are supposed to come cheap.
Meanwhile, the utterly reasonable $400 price on the Olympus 45mm stings a bit after I paid over twice that for the Panasonic-Leica 45mm f/2.8 macro lens. Still, the Panasonic has a focus limiter switch, can focus down to six inches, and is as far as I can tell optically unflappable, so I wouldn’t yet call the Olympus an obvious slam-dunk.
All told, the Micro Four-Thirds lenses available now cover like 98% of what most people need. The system is a few exotic lenses (tilt/shifts, extreme telephoto primes, maybe a 10mm prime for wide-angle nuts, f/2.8-ish normal and mid-telephoto zooms that will undoubtedly be relatively heavy and expensive for people with professional aspirations) from being a comprehensive alternative to the Canon or Nikon lens lineups.
No comment on the new cameras. If I were upgrading my Panasonic G1, I feel like my only reasonable upgrade would be the GH2 as I really prefer having a lot of manual controls on the camera instead of diving into menus.