It would be a bit of a waste to make a whole planet dedicated to just one or two classes, as that means they'd have to make other planets to fill in that gap in the plot for the other classes too.
While it might be neat to have a planet just for "your" class again after the starter planet, it would require a lot more resources than designing a planet with one, or both factions in mind. So again, not a bad idea, but I think Bioware won't commit the time resources to it. And even then any suggestions taken into account will be quite a bit down the pipeline as currently the writing team is currently penning stories meant to be added into the game in 2014, according to a recent interview.
I said "your" class and I meant the one you play. I didn't mean just one class entirely. Its not at all a stretch to imagine reasons for EVERY class to have quest lines there or even a non-class specific questline that isn't tied to the Republic or Empire. A trooper chases a Havoc Squad refugee to the planet. A smuggler is hired to get a shipment off world for one of the warring parties on Naboo. A bounty hunter is pursuing an escaped Jedi for some sinister Sith Lord. A Sith Inquisitor has heard of a very force powerful young child and wants to whisk him/her away for training. Same applies to the Jedi Consular but in reverse. The Jedi Knight goes to rescue the padawan of a Jedi Master who cannot go. The options are there, no reason not to explore every corner of this amazing galaxy.