Hillsilly said:
I wonder if they can make it a little lighter, shorter, give it the sharpness and AF speed of the f2.8 and make it fully weather sealed without affecting the price too much? IS is a nice idea, but I'll happily skip it if it means a big price increase. Like many people, I only venture into 400mm territory when photographing sports and wildlife and IS isn't going to help freeze action much better.
It's interesting that you would happily skip IS.
Obviously one wouldn't want to pay heaps but I think in this case about the general rule that without IS you need to shoot a 400mm lens at at least 1/400th to get consistently sharp images. There are many instances where you don't necessarily need a speed of 1/400th to stop movement of wildlife. If IS can help steady the lens so that about 1/60th to 1/100th are useable (and even slower), then to me that opens up many more possibilities for the lens.
I suppose it's horses for courses but when I had the original there were plenty of times when IS would have been handy.