Since you have made it to season 4, I guess you should finish the show. Gus is a businessman on the outside, but he is still a drug lord and a murderer. Walt is new to the business still. Perhaps if he worked at it for twenty years he could be like Gus.
The way the camera moves before Jesse pulls the trigger made it seem like he purposely missed, but the writers say that was never the intention. The cliffhanger is not "Will Jesse actually shoot Gale?" but rather "Holy crap, Jesse just shot Gale!" This show takes a normal slacker young man and a normal milquetoast middle aged man and puts them through the crucible. The journey is the best part.