There are some good shots of Cpt. Tarpulus and Jar jar that could be expanded upon. Especially before the battle, you could make a nice bonding moment where jar jar can say that he is proud to fight and possibly die for his people......then tarpalus can show equal gratitude in respect. Then there is the issue of cutting out all foul ups during the battle and portraying jar jar as a gungun warrior in the face of danger.
Perhaps you can give him a personality of someone who is outcast from society BUT ALSO is longing for adventure and travel. Have him bug the jedi at the beginning that he wants to follow them and possibly leave the planet. He wants to see what the universe looks like.....then of course with all the mess on tatooine, coruscant and space battles would make jar jar realize how much he liked being home with his people. I guess this would accomplished, as usual, by proper dialouge, voice over and editting to match the reactions of the human actors.
This could make the viewer sympathize with the creature, as this is suppose to be the FIRST introduction to the star wars unvierse....the audience WILL be jar jar: wanting to go through the adventure , not knowing what the universe looks like, not knowing all the details of the plot. Although I am wondering what trooperman is doing with jar jar for his ep.2 edit. Just a though.