How would the primary calculus change if Schock ran? Apparently he's had some initial meetings with the RGA already. A bit hard because he'd have to vacate his House seat (IL doesn't have LBJ laws, amirite?), depending on when the filing deadlines are for each race.
Illinois has the earliest primary for statewide offices in the nation (it is in February of election year, long before most state filing deadlines), and I believe it has the earliest filing deadline as well. The only states where you don't have to not seek reelection to the House to run for Governor are MS, LA, KY, VA, and NJ, for obvious reasons. (In certain states which are very far removed from DC, it is common to outright resign before your retirement to focus on the campaign -- Abercrombie and Heftel both did this in Hawaii, and it
may be a legal requirement in Arizona, I can't recall, and some people just do this anyway, like Deal did in Georgia).
How hard would the calculus change? The more conservative candidates there are, the better Dillard's chances become.
