First up, my bonafides: I've used Medium four different times. Two of my posts (http://sfbne.ws/17PPdPL) and (http://sfbne.ws/17PPhir) were editors' picks. And Medium even picked me as their writer of the week one week. (Which was sort of awesome, by the way.)
I think this assessment is a little off in a few ways. While I agree that the analytics leave a LOT to be desired, the thing that Medium excels at is amplifying an individual idea. Not necessarily a writer, but something that writer says. This is a big deal—it means that you don't need a platform to shout from anymore just to get traction. If the idea is good enough, thought out enough, relevant enough or challenging enough, Medium's staff will help push that idea out into the wider world.
I have a site with decent traction in the blogosphere, especially on Tumblr, and I know that if I put the ideas I discussed in those posts on there, they might have gotten noticed, but putting them on Medium had an amplifying effect. With my second post, about the Seattle Post-Intelligencer's decline as a newspaper without a print product, I got pickup in the media, including the Seattle press. The executive editor of the Seattle Times, the publication's direct competitor, tweeted it. And though I couldn't do it due to time constraints, a local radio station tried to get me on the air to talk about the post. And in the end, it succeeded at its goal—it got a lot of people thinking and talking about what we could do better about newspapers and advertising online.
My story directly contradicts his entire point about the "leaky faucet." That is a powerful tool and one that stretches beyond the individual blog. If you wanted your voice to carry that far previously, you needed to be Andrew Sullivan or Michael Arrington, or working for someone with a built-in audience and/or a lot of access. It has this amazing way of cutting through the niche and surfacing voices into the mainstream.
These days, everyone has a voice. There's more noise than signal out there. Medium is great at cutting through the noise and giving nearly everyone the opportunity to be a quote-unquote "thought leader," as cliché as that term is.
The fact that it decentralizes the voices, in a nutshell, is what Javier Sandoval is complaining about above. But that's exactly the reason why it works so well.
(Side note: If a lack of directly-trackable ROI is really a deal-breaker for you, you could always do what Narratively did with their recent post on Medium—they wrote a long item, gave a good teaser on Medium, and linked to the full piece: http://sfbne.ws/14KVNRj)