Well, remember that DL was a novel first, and then a campaign setting. While having ultra-powerful main characters and annoying races like Kender and Gully dwarves work in novels, where you can use them to further the plot, develop unique worldviews, and such things these plot devices sometimes do not translate well to RPGs.
Heh... see previous discussion on this point. DL was a series of AD&D modules first, and then a series of novels (which totally eclipsed the modules in popularity and became the canonical authority on the world), and finally a campaign setting sourcebook. Kender were introduced in the original modules because the creators of the world didn't feel halflings were appropriate to the setting; but I don't know how many of their more vexing characteristics were introduced there.
Raistlin was also introduced in the modules (as a playable character, in fact), but his ascension to Master of Past and of Present was a novel thing.