Funny, I think you've got the right conclusions with the wrong reasons. With inside english, deflection and throw do not work together to overcut. Deflection works to overcut, but throw works to undercut. There may be a speed and amount of english where deflection and throw cancel each other out just like you can achieve with outside english. However, I think it's much easier to find that equilibrium with outside english, because of the throw.
With no side english whatsoever, you've already got throw on a cut shot. The balls cling togather a tiny bit at contact, and the OB is dragged a little bit in the direction the CB was moving. The right amount of outside english can cancel this "contact throw" out entirely. Any amount of inside english will add to the contact throw.
So with outside english, you have to adjust less for throw. Deflection happens whether it's inside or outside spin, so I think throw is the reason some people find outside english easier to use than inside.
Oddly enough, I'm the opposite. I cut balls well with inside, but I can't seem to avoid undercutting them with outside. It's something I need to practice by running balls with varying degrees of outside english on every shot, which is a very good suggestion, by the way.
-Andrew