I wish his speed and capability was clearer defined, for instance how does hitting Mach 2 (twice the speed of sound) trigger time-travel? What else is going on there to allow that...?
But you are right that Barry limits himself, it has been strongly suggested in the series before that he is failing to fully embrace his potential. The Reverse-Flash is the one responsible for much of it as he very deliberately waged psychological war on Barry right from childhood and so when he comes in to his destiny as The Flash he isn't the same person as he would have been without the manipulation of Reverse-Flash. Of course though Barry as tortured soul is all good drama (forced drama at that) and I have little doubt that as with Clark Kent over the course of Smallville we will see The Flash grow up fulfull his potential by the time the series finally concludes. And therein is the point of course...
This is an ensemble cast television show, having Barry be fully capable, independent, and innovative in his approach as he was in his original series runs counter to the needs of drama and the need for that support cast. Plus he is just starting out after all. In a way though with Reverse-Flash overcome and his father exonerated and free one might think Barry would be on the way to believing in himself more, but the psychological scars left by Thawne have been there since childhood, he wasn't able to stop Thawne on his own, he was soundly beaten by Zoom, he is still relying on Cisco & Co rather than flying free... at some point he is going to have to win his own victories if he is to truly start to feel capable in himself and serve as The Flash in an independent manner. He must be the one in charge, and not deferring to others for every obstacle and dilemma.
Maybe that is who and what Zoom is, maybe barry from E2, or else a clone of him, who has reached his full potential?
maybe Dr wells made him into like a DC version of a Super soldier?