Remember this,
I’m sure Trump considers any VP he chooses will be the next president after him.
That is why Obama chose Biden, someone he could manipulate
as Democrats all march in straight leg lock step.
Pubbies not so much, so it is more difficult to make decisions as to your successor if you want an agenda to survive.
Obama knew for 2016, he would never be able to manipulate Hillary. He'd already screwed her out of the office in 2008, and there was no love lost there. So when he got his chance again, you're right, he picked Joe, because he's a mental midget that can be controlled. All you have to do is wave an ice cream cone or a little girl in front of him.