Some people like to customize classes without job stones, although the applications are very limited (i.e. I've seen B4B on marauder in T10 after echo with BiS gear & the healers' permission)

However, I agree that it would be nice to make the job system more obvious to new players or mention in a tutorial of some sort. I've had to vote abandon on garuda more than once when we had level 45 members who still had no job stones. Lots of people queue brayflox NM with no idea there's a job system, and are happy if it's mentioned to them.