There's a rather noticeable difference between burglarizing a house, and Trayvon's activities, which according to George's phone call with the police consisted of "walking around, looking about". George seems to realize this as well, which is why, in his walk through, he changes his story to Martin standing still and staring at a particular house.
That's a good theory but you don't specifically know why George's narrative changed unless you can read minds. Your suspicion is no more evidence of what "George is really thinking," than George's suspicion of Trayvon's presence is of what he was really doing.
And the evidence that George ran after Trayvon is, again, contained in his own police call, where he states that Martin "is running", immediately gets out of his car and begins running as well, and when asked if he's following, states "yeah". George, again, seems to realize that this is a problem, which is why he fabricates a story of him getting out to find an address due to the dispacher's repeated insistence on getting one. Although, oddly, he never did give that address to the dispacher.
We've been over the difference between following to see where someone went and following to detain someone. Until you have something to prove his intent, you are still relying on assertions, not evidence.
The reason why people suspect that he assaulted Trayvon is simple - all known evidence shows that Trayvon wished to avoid George, and that George wanted to ensure that Trayvon didn't get away.
I hate the annoying FIFY so I am just going to say flat out, the evidence you cited are still suspicions and nothing more. You don't know what Trayvon wished and neither do I. I can say the fact that Trayvon ran from that particular area and then three minutes later, he's back and involved in a physical altercation with the man he wished nothing more than to get away from is a bit problematic for me.