Awesomeness and the truth
I don't know how to describe it any more clearly, except on the KoTOR Sentinel and the TOR sentinel. Sentinel has always been the odd one out in the discussion and gets misconstrued a lot. In KoTOR his force powers and feat gain were average, but, his skill gain was higher. This meant the Knight could fight really well, the sage can use the force really well, but the Sentinel can handle all the tricky little details like locks, computers and repairs.
Lore area, skip if you want!
The whole point of this was so that the sentinel could do it's job, Jedi Space police. They were the ones who spent most of their time dealing with the peoples of the galaxy and rooting out the Darkside. They were the starting step for most of the Jedi Watchmen and Shadows. Because they were the ones who so often dealt with people, Sentinels often did a majority of the recruiting. Lore Over!
In TOR they're like the Knight's kind of crazy brother, two lightsabers and a whole lot of fanaticism. Want to be a Knight who hits stuff more? Take the Sentinel Advanced class.
Wow.. sorry for the rant on a small issue... I feel better now!