A friend of mine is currently researching the Sri Lankan blue whales and has had good coverage in the media (at least in Australia). I would think that any movement of shipping lanes would need a scientific basis with a realistic and effective alternative shipping route. Jumping up and down too much prior to having the science in place may discredit the cause.
Indeed, the situation is more complex and grim than initially thought. Change of shipping lanes isn't going to happen (anytime soon). Apparently, it may not even solve the problem. Still, I disagree with the notion that no action should be taken now. Compared to the long ocean journeys these container ships take, the blue whale hot spots are small and I don't see why one couldn't at least slow the ships down in these areas to reduce mortality:
Please do not underestimate the seriousness of this problem. They find quite a few dead ones every year and there are likely many more that are not recovered. For right whales, researchers worked out that only ~20% of whales killed by ship strike are found. Recovery rate in SL could be lower. The status quo is unacceptable. There are only two parameters that you can tweak: shipping route and speed. Research isn't going to show that ships need to go closer to shore or faster. So why not give the whales the benefit of doubt and act now?