Where's Worf? Presumably either dead at Khitomer, or serving in the KDF. Troi? Who knows? There were other episodes where Troi wasn't present either, but that doesn't mean she wasn't aboard.
But face it, the E-D is exactly the same. Same design, same command crew, even the same bartender
! Both versions of the E-D end up in the same area of space at the same time. There are far more similarities than differences. Apparently the disappearance of the E-C at Narendra had no effect on Picard et al.'s careers, or in ship design. I find it hard to believe that a prolonged war with the Klingons wouldn't lead to significant changes in ship design and personnel. Clearly the war isn't significant enough to change these things, so perhaps the war hasn't been going on for as long as it seems, or not at the same intensity anyway.
Perhaps this is a case of "for want of a nail". Perhaps the E-C saved a Klingon at Narendra III that influenced the Empire to be friendlier with the Federation. Or that one key politician or Starfleet admiral was killed early in the war that would have handled the conflict with the Klingons better. But the point remains that the Klingons, fielding the same ships against the same Starfleet ships, managed to kick Starfleet's ass in at least one scenario. More data would always be welcome, but for now it looks like the Klingons could defeat the Federation.