I think Abbott is most likely to win should he run again.
He might face a primary challenge from a more conservative republican. But it won't end well for the primary challenger.
Speaking of which, the Texas republican party needs to fire Allen West. He is causing lots of intra-party fighting and Abbott is the strongest on their bench. If West succeeds in getting his way and getting more extreme republicans to run, that might end up helping the democrats.
The best bet for democrats would be to run a Castro brother and try to get Beto-like fundraising. Still seems like an uphill battle against Abbott.
I also think that Paxton and Patrick will be more vulnerable than Abbott. But who knows if Paxton can even run again as all his skeletons came to light.
Perhaps MJ Hegar can run against Patrick.
This, please, Texas, please.