Missouri and Kentucky have already/are in the process of shifting R.
The evidence that Pennsylvania is trending R isn't that convincing. In 2012, its PVI was D + 1.48, which is the lowest its been since 1996, when it was D +0.7. The PVI has been decreasing since 2004, but its not clear if this is a real trend or random fluctuations.
Iowa is interesting. Its demographics would tell you that its a Republican leaning state, yet its consistently been a swing state. I don't think that's going to change, but I suppose we'll have to see how 2016 will play out.
The problem Democrats have with whites is a southern problem. The rest of the country's white vote around 45 % Democrat. Southern racist whites skew the number nationally. Iowa should be fine long term.
One state to worry about long term is PA. The Democratic collapse in the western appalachian region is good news for Republicans.