The Trooper a strong contender for just about any role in the game except for melee combat (and even there it has a few moves). It can heal, deal ranged damage, and tank alike, so I'm not surprised to hear that there are all-Trooper guilds forming up for the game. If you like having wide-open possibilities for your character's future roles, the Trooper is the way to go.
The Trooper begins his journey on the war-torn world of Ord Mantell (alongside the Smugglers), where he's been recently recruited by the elite Havoc squad to tackle the toughest missions out there. You may not feel elite at the beginning, with light armor, an aged blaster rifle, and only a small handful of skills backing you up, but trust me -- by the end of your journey on Ord Mantell, you'll be ready to rock with the big boys.