The last two Vice-Presidents were from two states with the minimum allocation (3) of electoral votes -- Wyoming (Cheney) and Delaware (Biden). Neither was from a state that anyone thought in doubt in the Presidential election.
Dubya chose Cheney for his alleged skills as an administrator.
Obama chose Biden because Biden was the poorest Democrat in the Senate -- someone with no possibility of any scandals for personal gain.
Thune? What does he have to offer?
Thune is a "safe" pick; he won't make mistakes and he's fairly well vetted. He "looks" Presidential, and he's acceptable to the whole of the GOP.
Thune may be boring, but he's not the kind of guy who'll be the World's Loosest Cannon. He'll be message-disciplined and if he doesn't help a whole lot, he won't do any harm.
That's the same rationale that led to Paul Ryan getting the VP nomination.
The problem with Paul Ryan was that he was a sitting Congressman. He had never won a statewide election, as is typical of a Congressional Representative. As the Presidential election faltered, Ryan reverted to defending his Congressional seat. Thune has no such problem. He would not be another Paul Ryan. If he can 'run' for his Senate seat against a disorganized South Dakota Democratic Party he wi9ll be able to run for both he Presidency and the Vice-Presidency.