Laird, exo-planets and solar system planets are not the same. What's true for one isn't necessarily true for the other. If Venus had an unusual origin, it wouldn't be orbiting the sun in the same plane as all the other planets, and have the least eccentric (most circular) orbit of all.
Good argument, but entirely disputable. I won't rewrite my book here, but there's lots and lots of evidence to the contrary.