I know I'm going to iritate some Flash fans who think I just don't know enough about the character, or the history, or the story at all, and, well; yup. But I know what's going to look good on screen and what won't; and a screenshot of a guy in red speeding across the globe to stop a bank robber won't work.
That's why you spin this thing backwards. Certainly don't focus on his speed, so to speak. Let me back up. For the sake of a loose plot I say Barry Allen keeps the police scientist backstory, stumbles on some type of terrorist-state chemical weapon and, as he makes the discovery, the U.S. Military, who never alerted the PD that they were about to make a move to destroy this stock pile, uses some type of electro-shock stabilizer to neutralize the chemicals on board (destroying them would put the city at risk). In this event, the Flash is born.
But he's not the Flash to us. And he doesn't even understand that he's the Flash at first either. His first episode could come from a cancer like trauma event over the toilet a week later and during the episode, he walks outside to see that no one is moving. He panics and passes out, waking up later with his partner sitting next to him explaining that he found him asleep in the middle of the police station.
Fill in the rest (love interest, etc.), but in my opinion, this guy works if you focus more on his new found focus, ability to see things clearly (which we learn of course is just speed), a focus that allows him to see everything in slow-mo (so he's fighting like he's in the Matrix, and moving through the world as if the place is spinning backwards).
The coolest way to bring in this effect in action for the first time would be if he was attacked after his episode in town, and, activating his powers accidentally, (the theme music from Tron comes on, when Sam jumps on the grid-bike for the first time, and everything is in slow-mo, perfect music for revelation style slow-mo), and he sees everything clearly, the guys get their a**es kicked before (in their mind) they even moved, and when they come to, the Flash has already disappeared.
Again, I'm no expert and I'm sure I'll get no love for this post, but I'd like to think I had an idea for what the movie would look like before its released; because if they introduce him like that, I WOULD pay to see a Flash movie afterall.