I feel that that's because the Comedian, of the Watchmen characters, has the least recognizable character parallel in the DC comics. Plus he, Rorschach, and Doctor Manhattan seem to transcend their inspirations the most. I mean how often do you really see Peacemaker nowadays really, ya know? Most people who would see The Comedian and Peacemaker now would recognize The Comedian first and probably find him more compelling. Poor Peacemaker got John Carter'd lol
I think the characters that would fit the DC universe the best would be Mime & Marionette imo but that's kinda a cheap answer seeing as they essentially are DC characters. Barring them, I would love to see Ozymandias in the DC universe more than The Comedian.
I feel the sonning that he would receive being in a universe with more big brains than just him; many being bigger brains. and the inevitable bounce back as he discovers and starts to master all the crazy science shit in the DC universe would be amazing. I imagine it would be like if you took a real life scientist polymath and dropped him in the DC universe.