I'm not opposed to time travel stories no, I am just critical of using them to launch a show like this which isn't about time travel!
Barry Allen's life is one huge time paradox according to this television launch, which while very entertaining I find rather odd and problematic going forward...
As I recall in the comics the whole Flash/Reverse Flash thing is a major time paradox in and of itself.
Also Barry was still struck by lightning and blasted into the chemicals in his lab which were also agitated/stirred up the weather. There is no overwrite of Barry's origin. Wells/RF simply made sure that it happened via the particle accelerator.
I still believe that RF is bound by the "power of history" as it were and that while he'd love to kill Barry and the others, he cannot.