Media market locations could also play a factor; I've heard it as an explanation before relating to why New Jersey always gives horrible approvals for everybody- I notice Delaware also has low approvals compared to other states its size, and it's in a media market situation just like NJ. Don't know how you could quantify such a thing, though.
Thats a good theory. It may explain why Jodi Rell has always had undeservedly high approval ratings, we're split between the NYC and Boston media markets, neither of which covers us at all, and the local stations don't have much impact.
What media market is Delaware in? I suppose Philadelphia but it could be Baltimore too.