Strawman. What I (or anyone) thinks of Generations or Insurrection plays no part on the quality - or lack of - in Nemesis.
Supposition. Frakes may just as easily have hated the movie for being rubbish.
Nemesis suffers from a poor plot, a bad villain and - shock, horror - recycled plot points. Add to that pointless car chases and characters acting completely out-of-character.
Nemesis was only dark because of the low lighting levels. Other than that, it was about a campy, 2-dimensional villain, poorly veiled to appear serious and moody.
Nemesis was nothing more than a film that wanted to desperately be Wrath of Khan.
The only comparison between this new film and Nemesis appears to be that the antagonists are Romulan. Except, of course, in Nemesis, the antagonist was human and aided by Remans. The only other comparison is that they had weapons of mass destruction.
But then Shinzon's radiation gun was little more than a poor man's genesis device. The entire end of Nemesis plays out just like the end of Wrath of Khan. Villain's plan fails and therefore attempts to destroy the crippled Enterprise, but fails due to a beloved character sacrificing himself for the crew.
At least Nero had a real beef with the Federation. Shinzon had a lifetime of hatred for the Romulans, so when his opportunity of revenge arrves, what does he do? Attack Romulus? No, he decides to attack Earth.
There's next to no similarities between the new Star Trek and Nemesis and Nemesis is far more guilty of ripping off older Trek films itself.