Talking about the Gov of DE seems a lot like Cook County, IL and the office of board president. Cook is about half the land area of DE, but has five times the population. It's the only county in IL granted home rule status so the county board and president have a lot of authority over taxes and regulation. And like the GOP in DE the GOP has no chance of gaining the Cook presidency.
And yet even small state governors are imputed to be potential presidential material, unlike the heads of much more populated large cities and counties. How big is Chicago, NYC, LA, compared to AR, AK or MT? And yet Clinton, Schweitzer and Palin could all be considered presidential candidates (or at least legitimate Veep picks), unlike the mayors of municipalities with vastly larger (and usuallly much more diverse) populations and budgets.
Guliani was of course an exception, but only after 9/11 "nationalized" his standing beyond being a good executive to foriegn affairs/terrorism issues.