In this era of Dual-statted books, there is a big difference between "changing/adding stuff you think is kewl" and "changing/adding stuff which will GREATLY aid the dual-statting process." Everyone knows that one of the most popular types of superhero sourcebooks is Rogues Galleries. Books full of villains and characters to populate the setting and adventures with. Whether you look at DC Heroes, Marvel SH/ SAGA, Champions, whatever, these are always the most common and most useful books for a superhero game. But NONE of them has ever been dual-statted before...
If the games are so far apart that each character requires an entirely seperate page of stats, you are literally wasting half the book. Imagine a dual-statted Champions and DC Heroes/MEGs character book... every character would need totally seperate stats for each system, and chances are the character would not be very balanced between the 2 systems.
I initially feared that Tri-stat and d20 SAS would be like that, and as much as I love the game, if it were that different, every Roster book would contain 50% useless information. Considering that they already have at least 3 of these types of books on their burners, I feared a disaster... But then I saw how similar the systems were. Only a small box with stats, attack/Defense values, Health, etc needed to be changed for each character. The powers, skills, and defects remained the same. This meant a bare minimum of wasted space, and it made Roster books a viable possibility.
If GoO wanted to just print a d20 Supers game and then not support it (as many small d20 publishers do with their core books), I'd agree that staying as close to D&D as possible would have been a smart move. (Everyone knows D&D players are totally unwilling to learn another system, right? That was sarcasm, by the way) If they had planned to support the line with a series of NON-dual-satted books, this still would have been the smart way to go, maybe. But if they planned to support the game with dual-stat books as they are, it would have been suicide to TOTALLY change the system over to D&D, instead of just doing a d20 varient as they did. D20 gamers would have been pissed that 50% of the book was taken up with Tri-stat powers, skills, defects, etc, and Tri-stat players would have been pissed at page after page wastyed on descriptions of Feats, different skills, etc. I submit that this is THE ONLY WAY a company that wants to support a game with dual-stat sourcebooks focusing on Villains and Characters can possibly do it.