I leveled watchman all the way and i did hit a wall late 20s early 30s, probably because of gear and it was early days of the game, but once i got doc there were no problems.
Sents are all about damage and speed. Use your burns, stay geared kill small to big but keep killing and go fast keep the focus up and keep sabers charged.
in city of heroes we had a thing called scrapperlock were that class just moved quick and killed everything in fron of it. its the same thing with sents and mara. I know when i play on my tank in fps i like to go slow and measure the fights and make sure all details are covered and the sents and maras want to kill them, kill them all and kill them now