I admit i am not a fan of d20, or the existing lonwolf rpg, but having got the latest startwars streamlined d20 game, i think the d20 lonewolf rerelease could be adapted pretty easily. Apart from reducing unnecessary die rolls (no separate concealment and cover rolls, no second crit roll, no saving throws etc), i think its strength is doing away with rigid level based class features. Basically, every class gets a Talent every other level, which is chosen from various themed Talent trees. some have requirements, such as particular feats or talents, but usually you can pick and choose however you wish, rather than forced to take certain features at specific levels. In Starwars the classes are more generic, since multiclassing is easy and pain free. many of the Lonewolf classes would simply be "prestige classes". So, for example, a 13th level Sommlending Knight of the Realm, would maybe be a 4th level Soldier/3rd level Noble, 6th level Sommlending Knight. Sounds more complicated, but actually creates much more choice from a players perspective (the same character could be a 2nd level Rogue, 7th level Soldier, 4th level Sommlending Knight.) I may tinker with this .....
I would also separate race from class ( a personal bug bear of mine with lonewolf d20) So players could play an Ogron Soldier, a Noodnic Rogue or even a Kloon Noble.