You see Chris, I agree with Bird on this one. There is just way too much going on for Ratatouille to add on to the "important stuff" that Linguini should be able to grow as a chef because he's Gusteau's son. In fact, the only two reasons I believe Linguini's revealed to be Gusteau's son are: (1) for him to get hooked up with Gusteau's "true son" who teaches him things but cannot convey the true love which Remy has. Remy is actually Gusteau's son, if not genetically, at least through that damned TV/cookbook and the way it convinces him to "rise above his station"; (2) Linguini has to foil that scumbag Skinner who's completely selling off the Gusteau name and is a hilarious character who needs to be put in his place. That, to me, is the entire reason that Linguini HAS to be his pop's son, and not to learn something because he is. If you were going to incorporate that subplot into the current version of Ratatouille, it would have to be at least two-and-one-half hours long. So I say, no thanks. If you want to explore it, you can put it in Rato 2: The Revenge of the Yucky Nibblers.
I guess it just comes down to which is more important to any given moviegoer. I find myself bored and exasperated most of the time Linguini's on screen, and I'm not used to having to make excuses for any Pixar character, really. But if the idea of them being two halves, or two conceptions of Gusteau's "son" is striking enough to you, I could understand why it wouldn't bother you. To each their own, of course.