The biggest issue preventing big ticket free agents from coming to MN is money. We don't offer it. No other factors matter.
We rarely pursue mid-range free agents. Other factors start to play a role on those we do pursue. Of these factors, my guess is the biggest is a perception this team isn't serious about winning. You don't come to Minnesota expecting ownership to commit extra money if needed.
On Low-level free agents, many and varied issues come into play, depending on the player, but I'd bet opportunity for playing time is the biggest.
I doubt taxes, weather, "fly over country," or media bias plays much of a role for anyone.