Oh leave cossack out of it. He HAD a kid, so theres no reason to make "some super robot to continue his legacy" cuz his daughter is gonna grow up and have kids of her own, which are going to grow up, and have kids of THEIR own, and so forth.
Wily and Light however, never got laid, and never had kids, not to mention Wily has GOT to be sterile from that lab of his. therefore, they keep on going at it, like the sexually frustrated super nerds they are, making super robots which are supposed to fight each other once their dead. Wily, in his final years, became so crazy by his inability to get a boner that he made his robot look like a girl. Light grew out of little boys and girls, and made his a teenager.
and there, my friends, is the transition from Classic to X, in my nutshell.
but I digress.
On Dynamo, he should remain pastless. (as in, not some robot created by some "special" scientist.) being just a normal reploid makes him such an interesting character in the sense that hes an average, (well, slightly ABOVE average, but still a standard Reploid)reploid with battle capabilities. he wasnt made by some long dead famous scientist and is as unreadable as moonspeak put through babelfish, or made through mysterious means as the test version for some new breed of reploid. just a main character that is a ordinary reploid, if you get my drift.