My big hope is, that the Sentinel and especially Watchman will be a little more useful in KotOR:TSL. In KotOR1 I always preferred Sentinel over Guardian and Consular, because I didn't want to use the force well and be a really weak bastard, who would be struck down by Malak with two hits - and vice versa. I wanted to be something equal. But horribly I found, that the Sentinel fights as well as a consular and uses force as well as a guardian.
The Sentinel should have it's own strenghts, i.e. he had immunity to fear and stun, but i'd say, give him a total immunity (like Force Immunity, but always active). And because of the equality of the class, it should still have a little piece of Consular and a piece of Guardian. i.e the consular had three levels of Force Focus, the third level (master force focus) gave the consular +4 DC to force powers. I would recommend, that the sentinel should have at least the first level of force focus, what would give him +1 DC to force powers. And also they should include a slightly bigger attack bonus, than the consular has, to bring the sentinel a little closer to a Guardian.
And of course, they could always punch in some more free feats..