No, he was talking about the hardware and the porting capability: https://www.gamespot.com/articles/valve-says-wii-u-fits-better-with-its-tech/1100-6320886/
But that comparison was Wii U vs. Wii, not Wii U vs. 360 or PS3.
"Wii U seems to be a lot more powerful than the previous generation," Valve Corporation president and cofounder Gabe Newell told Joystiq. "It sort of fits better into the scalability in terms of graphics performance and CPU performance, so I think it'll be a lot easier for us to fit it into our scalability model... Now it's a lot easier to look at Wii U and have it fit within that framework."
Ah yeah he was saying that in 2011 :P Wii U launched on the tail end of 2012 and then other consoles released in 2013.
And he was talking about the specs from Wii U from Wii. Which, to be fair is a big jump from the latter.