Normal starting play is likely to be overlooked in favor of Knight Level, especially with the handout lightsaber. The whole thing is just too dangerous.
I would even go so far as to recommend that the whole option be removed, since I really don't think GMs need a rule to tell them how the give players more XP. All this does is set an expectation for the players and force the GMs hand to use it. If GMs want to start their group with more XP and gear, fine. But it shouldn't be some special, game-unique thing that you can only do here (as opposed to EoE and AoR) and need some special rule in order to do.
Talking about extremely and negatively loaded words why define Knight level play dangerous? I see no danger in wanting to play with more experienced characters so you can actually create more complex charcters than the "farm boy/girl who wants to escape his farm and see the stars" or "runaway guy from Nar Shaddaa who picks up a blaster and starts hunting criminals". You're talking like making anything higher than starting charcter is game breaking and wrong.
How would you run an Old Republic F&D game? Not everybody will find playing Zayne Carrick appealing.
As for the special unique thing that you can only do here, i haven't read anywayere that you can't do it in EoE and AoR, i take it for granted you can do it and you actually should do it if you have a mixed group who wants to start as knight-level.
In these games there is nothing you can't do.
Your character is as complex as you make them, not the numbers on your character sheet. I have a fairly complex character with a rich background and tons of tie in options, yet she is inexperienced. Just because she doesn't have a bajillion XP and 5's in all of her characteristics doesn't mean she isn't complex, nor does her low Force Rating mean that she is any less complex than any other possible character. You don't need XP to make a good, enjoyable, or better character.
Now, how would I handle experience in an Old Republic game? I wouldn't, for a variety of reasons. The first of which is that I think the Rebellion Era is the more accessible and interesting of the time periods to play in. Second, the game is set during the Rebellion Era, and that fits me like a glove. Third, the Old Republic is so full of power fantasies and nonsense that I really don't want to touch it. And fourth, and most importantly, as I have already mentioned, you don't need more XP to make a good character.
And to make this perfectly clear, I am not badwronging people for playing games with higher XP. I'm a huge advocate of creating a preamble for one's game and having players make characters appropriate to that (with defined starting XP and all). But what I'm not interested in are the expectations that people tend to bring to this game. It's always Jedi this and lightsaber that. That's not what this game is about. This is not an FPS with a single dimension of play. It is those expectations that players are bringing to the game, mixed with hard the advice that GMs should be handing out lightsabers at 150 XP, and this whole nonsense with Knight Level play that are creating false ideas about what this game is and what characters are and are capable of. Taking all of the nonsense out and simply acknowledging that GMs can, if they choose to, start their game with a higher XP level instead of creating some exclusive play mode with an incredibly loaded name is going to clean up a lot of problems.