It seems if I can paraphrase your argument that it boils down to: "Just because your drug works in a mouse doesn't mean it will work in a human. So even if it works in a mouse there is still a lot of technical and scientific risk left."
I certainly agree with that. But I don't think it's incompatible with what I wrote in the blog post. The way the economics of the pharmaceutical industry work, it is still worth taking drugs into human trials even if the chances of them working are small.