Hes only whiny in the first act! And its done on purpose to establish character ya dick!
That's my biggest problem. Even though he didn't know Obi-Wan for very long, I feel that he should've been more grieving than crying for 30 seconds - 1 minute and then act like it never happened. I'm not saying that he should've been going about crying, but it feels like Obi-Wans death had almost no impact on Luke. I mean, the movie would've worked perfectly fine if Obi-Wan didn't die, just use a radio when luke is in the fighter, and the rest of the time, Obi-wan is in a form where you can see him, so him being there would've been just as good.