Heh, Paul reminds me ever so slightly of Sasuke from Naruto...
Anyway, Paul is a very interesting character with a different view on how Pokemon should be raised, which makes that much more interesting. I'll be very dissapointed if we don't get an insight into Paul's background, especially because he is so different to his older brother, Reiji.
I'm not a huge fan of how he battles but he gets the job done, that's for sure. Which, in regards in to Leagues and Gym Battles, is the most important thing. I've never liked releasing Pokemon either, but that's probably because I don't do competetive battling and generally don't care if the Starly I catch at the beginning is Level 2 or Level 5.
Overall, Paul is a good character to have and should stick around. He has his flaws, just like every other character, but that doesn't change my opinion.