Yes, maybe the IPCC should have concluded that we have no idea about climate sensitivity. But they needed to put some sort of estimate range that could be fed into their scenario analyses.

Anyway, I found an infographic of different climate sensitivity estimates here:

http://www.cato.org/blog/still-another-low-climate-sensitivity-estimate-0

Direct link to image:

http://object.cato.org/sites/cato.org/files/wp-content/uploads/gsr_042513_fig1.jpg

PS: I have no idea if the infographic accurately reflects all recent studies. The author is a global warming skeptic who has received money from oil and coal industries, so that should be cause for skepticism. But I think such an infographic would be hard to fudge. If anybody has a better source, I'd be happy to hear.

UPDATE: Added it to post at end of discussion of climate sensitivity estimates.