Picking an AC needs to mean something people! What the &$%# do you think this is, a game?!
People, if you think gaming needs consequences to prevent other people from breaking your sense of immersion, you need to back away from the keyboard and spend time outdoors.
I have RL friends in the military who have changed their specialization several times over a career. Sometimes they weren't suited to their initial choice, sometimes their field was full and other roles needed to be filled. Not once did their superiors complain it was unrealistic because "if you wanted to be a rogue you shouldn't have rolled a mage".
I know using real-life analogies might be a weaker argument than pointing out that SWTOR CAN'T do something because that's not how other MMOs do it, but I'll risk it.