Honestly, I'm not sure if I think any of these should br flagrant fouls. Most of these are just bad circumstances where people are going for the ball and the recipient just ends up landing badly or accidentally getting hit in the face. To me, flagrant fouls should reflect ill-will or malicious intent, not some abstract term of "unnecessary" contact.
That chop with the arm(s) swinging down that you can see on Walker and Sullinger's fouls is an automatic flagrant. If you don't realize this, you aren't watching the NBA 
You're making a descriptive claim saying how things in the NBA. I'm making a normative claim saying I don't think they be that way. I mean, I think Sullinger's foul and Walker's foul specifically should not be flagrant.
The problem with the current criteria is both that it is vague and it isn't consistently called. For example, if Gibson or Morris had not ended up on the floor, they would be common fouls. People swipe down all of the time, but it's only called when it looks bad and the guy falls down to the floor. However, that's not part of the criteria determining those calls.
Excessive contact only refers to F2 calls, so I don't see how "unnecessary contact" can be a reliable criteria for flagrant 1 calls.
Harden's kick to James' groin - that's a flagrant 1 to me for not being a basketball play.
Artest's elbow to Harden's head - that's a flagrant 2 to me for not being a basketball play and for being excessive.
Smart's trying to draw contact for the and-1 move - that's a common offensive foul to me.
He was making a basketball play, where the other two weren't, and I don't think he was trying to elbow EP in the head other than just trying to find contact. That's where I fall in the flagrant foul spectrum.