I like this....while the extent of the book's impact is speculative, at the very least the argument that Cold is the first significant Silver Age villain creation is a significant point. At the very least it's a great argument that the book is still underrated.
I'm not sure that Marvel doesn't happen though; when you look at the Challs then look at some of Stan and Jack's early efforts (Dr Droom, TTA27, TOS 32, Two-Gun Kid 60, first two costume-free FF's) the idea of uncostumed sci-fi type heroes with regular guy lives seems to be percolating for a while. The Spidey of AF15 isn't much beyond this; the costume is a vehicle Peter's efforts at celebrity. Things moved quickly, and he was the turning point, but the same seeds were there.
I also like the argument for the impact of Flash 123; this the Avengers 4 of the DCU. While Showcase 4 and 8 and FF1 may have birthed the silver age, the role of Avengers 4 and Flash 123 in ensuring the momentum is sometimes overlooked. Through two different routes, these books bring the Golden Age into the Silver Age, and the concept of continuity is brought to the forefront.