I can see how those who like to walk around with a 25mm lens might find a 12mm or 14mm to be a good counterpart. But for some of us who like to walk around with a 17 or 17.5mm lens as our wide "normal" - and there are a lot of us in that category - a 10 or 10.5mm lens may be a better complement. We've got a bunch of options at many of the focal lengths. The only primes we have at 10 or 10.5mm are quite heavy (Voigtlander, Rokinon) or not the greatest performers for landscape (SLR Magic). I've long been expecting to see Olympus or Panasonic bring something out. Still waiting!