The idiots should made Exar Kun, not another freaking Maul or Fett.
I hear you on wanting an important EU character like Exar Kun. But I think you need to try shifting your perception of figures like Darth Maul or Boba Fett in this case. Try to regard them as the anchor pieces in the sets.
In the SITH LEGACY, it's Darth Maul that's featured on the packaging. He's the mainstream draw in that particular set. While a good deal of more hardcore fans might know Darth Bane and Darth Nihilus, the mainstream people probably don't. Also, this Maul is a good update on the POTJ figure that came out with the training droid.
And with the FETT LEGACY, again Boba Fett acts as the mainstream draw. Plus this version gives as a super-articulated version of Boba Fett as he appeared in Empire. Oh, and they threw in that cool removable helmet, too. Now the flipside is what would you offer in place of Boba Fett? That would make Jango Fett the anchor in the set, but who would you make the third Mandalorian in the set? Canderous Ordo? You can pick any one of a number of Mandalorians, but the OT would no longer be represented in this set. And that's still a big selling point for some collectors.