He is absolutely right (But in classic Sony fashion a bit misleading)...
Graphics rendering (Or using the cloud to directly improve graphics quality) is absolutely not something that works well in the cloud...
However, data calculations, math, and logic is (Which is what the XBox One is designed to be able to do)... Now, it shouldn't be a hard stretch to understand that if the console itself doesn't need to do these other (Data intensive) calculations, it will be freed up to focus more on graphics rendering.
Hence, indirectly allowing for improved graphics...
At no time did Microsoft (Or anyone) suggest that they were actually rendering graphics elements in the cloud. LOL In fact, they were quite clear (One of the few things they explained) on what was going to be offloaded to the cloud (If the developer chooses to).
the only thing i've seen mentioned and beat like a dead horse is
"While latency-sensitive actions will be handled by a user's Xbox One console, Microsoft claims its cloud architecture can pre-calculate elements like lighting and physics modeling, leading to increased in-game performance."
Of course there is lots of robustness on interactive worlds and dynamic / changing conditions based upon near real time user interacticity.
lighting and physics modeling can be terribly expensive and if you "cloud" enable that, that certainly does open up lots of opportunity to do other things with the always finite local resources.
I'm still not sure how sony doesn't see that as viable/possible or apparently not worthwhile. The only safe thing to assume is that Sony didn't engineer for such at all while Microsoft did and it will be up to the developers to prove the concept out.
All that being said, the "Cloud" is a huge enabler - an opportunity for people to challenge the status quo. It certainly isn't a hinderence.