It seems to me that much of the discussion about new lenses revolves around how much faster they should be. This would obviously result in bigger (and more expensive) lenses as well. The more I thought about it the more I remembered the main reason I went with m4/3 instead of another format was size and weight. So I am trying out a 300/6.3 Pentax Takumar to possibly replace the Nikon 300/4.5. It weights about 450g less and is much smaller overall. I would lose 1 f-stop but also about 1 lb of weight as well in my bag. Plus it can fit in my smaller bag where the Nikon can not. My hope is that Panasonic and Olympus will work hard on improving ISO performance more than making faster lenses. I believe that will benefit me more with ALL of my lenses than just getting a bigger, faster one.