If last year had been a normal year and Parish had spent those games in the forward pocket, it might very well have hurt him compared to playing in the VFL on the ball. I have no doubt playing forward in the AFL team rather than in the midfield hurt Jerrett's development (not saying he would have made it, just that he performed worse due to it).
At VFL level Francis will get the first defender, and be the focus of the attack. That lets him develop the skills to handle that, to being the focus of the opposition and your own team. At AFL level he'll be a third tall with no engine who is bobbing up for the occasional goal. I don't see the development he'll have in the AFL will be at all the match of what he'll get in the VFL.