I did the walking away from TOR when I couldn't make a Chiss Force User unless I rolled up a class I didn't want to play and get it to 50 first, I left. When all I had to do was get to level 10 to make it, I came back. So it's not like I don't take my own suggestion.
That was a mistake - I implore you, play an Imperial Agent. Of course it's a matter of taste, but the Imperial Agent storyline is considered to be by far the best, not only by myself, but many players as votes on the topic indicate.
Technically you can of course unlock the class by other means. I have exactly three level 50 characters - Twi'lek Consular (Infiltration Shadow), Chiss Imperial Agent (Marksmanship Sniper), Chiss Jedi Knight (Combat Sentinel).