every class has a role...
the question is really finding a class that suits the way you wanna play...
healers are great, and there often arent enough... but then again, they cant really do much on their own (not that they have to, quite the contrary), i just think a lot of people choose having a powerful sort of a character over something like a healer (even though healers are just as useful)...
i made a scout, which i like a lot... most of your usefulness, once you are developed, is for recon/spying type stuff... you aren't going to be particularly powerful in a fight... but scouts are great for putting theives/assassins in a bind ;o