For a fast telephoto zoom that is. Given the regard that the 17-55mm f2.8 IS is held in, should they be looking to build on that with an f2.8 EF-S lens of around 50-125mm? There's no obvious signs of Canon moving away from the APS-C sensor format, so wouldn't something along these lines be a popular decision? Presumably not everyone want the cost or weight of the 'L' series stuff, as good as it is. Are Canon missing a trick here?