I dunno, personally, aside from the vehicle levels, SOTE just isn't that great IMHO, especially when compared to JK.
Sure the graphics in places are prettier, but the story, characters, etc are less interesting, plus the levels are just not as complex and vast. The controls are a bit junky too, and first person combat-wise, SOTE is pretty simplistic. And of course.. no multiplayer or editing.
But, hey, each to his own. ; )
I think they tried hard, but SOTE did have a positive outcome: it gave rise to JK and RS. Each of those games focus on an element from SOTE and do it far better, IMHO.