So far Jonathon Frakes, Marina Sirtis, Levar Burton, and Wil Wheaton have chimed in, and all except Frakes lay the blame squarely at the feet of director Stuart Baird. Frakes lack of direct blame seemed to be more diplomatic than anything else.
I didn't review Nemesis here on the site because it was released about a year before I started Screen Rant, but if had reviewed it, I probably would have given it 1 1/2 stars out of 5, tops. It was so terrible it's not even funny, and in the post-mortem it infuriated me that Rick Berman blamed the film's poor performance on the audience. I'm continually amazed when studio execs blame an audience when a horrible movie doesn't make a decent profit.
I thought it was so bad that I told my sister (a long-time, hard core Trek fan) not to even bother to go see the film. When she finally saw it on TV recently she agreed with my assessment completely and was disgusted with it.
Here is one of Wil Wheaton's comments:
"...a director who said more than one time on the set, 'I don't care about Star Trek'...one thing can go wrong and the whole thing falls apart."
When Levar Burton was asked recently why Nemesis bombed, his reply was:
"That's because it sucked!"
Both Burton and Sirtis have stated that Baird knew nothing about Star Trek and that he couldn't even remember the name of Burton's character, LaForge, calling the character "Laverne"!
Of course doing a little digging we find that this was precisely Rick Berman's intention. A quote by Berman while the film was still in production:
"When I met with Stuart, who didn't know a damn thing about Star Trek, but who had read our script, his approach to it I found fascinating."
Frakes' comments include:
"the show didn't focus strongly enough on the TNG characters."
He also stated that he really wanted to direct the film, but personally I don't know that this would have helped much as I haven't really liked the the two Treks films he's directed. First Contact was ok, and is the best of the TNG movies (although that's not saying much, IMO). Let's not even talk about Star Trek: Insurrection. (shudder)
In any case, it's good to hear that some folks on the inside agree with some of us on the outside.