I think that the original purpose of the starter classes was to give people some flavor of the play style before making them commit to a specialization. I suppose this worked all right (although I'm not sure how much playing ten levels as a counsellor helped prep you to play a shadow, to pick one example). Plus, you got your advanced class when you got to the fleet for the first time, which was kind of a cool milestone for your character.
Changes in levelling, I think, have made this original approach less viable. Classes level so quickly now that you don't really spend enough time in your base class to give you much sense of their play style. For my DvL toons, I made it to lvl 10 about halfway through the starter planets. So, I guess I don't see much harm in having people select advanced classes when they roll, rather than ten levels later. After all, complexity should serve logic and enjoyment, and not simply be retained for its own sake.
What puzzles me is some of the more specific changes. Assassins without lightening? Why? That's one of the cooler animations in this game, and I don't think that anyone was arguing it was OP on 'sins, so I don't understand the reasoning in removing it. Ditto for some of the other changes.