The character of Doctor Faustus certainly coincides well with the tragic flaw theory of character development. From the opening lines, the reader already gets a sense that Faustus has an insatiable desire to attain knowledge which will confer power on him. His desire for this knowledge, particularly his view that he is entitled to it, is his tragic flaw. As his character develops, the reader is meant to understand the corruption that inevitably coincides with the pursuit of such knowledge, as well as the blindness to potential consequences.
The last lines of the play effectively summarize the lesson to be learned - a lesson which springs from the outcome of Faustus's tragic flaw. He aspires to too much, and in doing so he gets what is rightfully his. An excess of anything becomes a bad thing. Faustus's excess pride and intellectual curiosity ultimately consign him to hell.