Lets hope not at all. In case you didn't notice in the movie, they were more or less pathetic in every attempt at battle, their strategy was to hide behind a shield until the enemy got close enough for them to stab and grenade. The only reason they weren't massacred(unfortunately) was because the capital ship was destroyed. Even the ewoks were more intelligent than the gungans, they managed to create defenses against vehicles that didnt require suicide charges by possibly mentally impaired gungans like jar jar. And to your comment on just dont play them, heres an idea, instead of wasting time with sides that most people agree were terrible mistakes against filmmaking, humanity and intellegence, lets just spend the already not enough time given to the game making real sides good and skip the stuff that everyone will hate because they have to hear gungans speak every time they play.
Whether you like it or not the Gungans are part of Star Wars in a BIG way.
We know of the city they live in plus many vehicles and animals they use and fight with. If other factions are going to be added there is more content adding them then most others.
Again it should only be one faction of many and if you don't like that one don't play it but as this game grows the Gungans are eventually going to invade this game.
http://www.youtube.com/watch?v=kYfibSaDHrM)