I think it was a bad idea to redesign the ships, but then again it is not my creative content and Chris Roberts has the right to take it where he pleases.
Millions of Star Wars and Star Trek fans would disagree with the notion that whoever invented the creative content has the right to take it where they please. The fact is, very frequently the creator of something get's the idea that since they created it, they have a better idea than anyone else how to make "it" better. Unfortunately, they're often wrong...a less biased eye a little further from the subject can often make a creation even better, while the creator often does not see the flaws in his own perceptions.
Example include Star Trek TMP (which is why they basically railroaded Roddenberry off the project when they made STII), all of Lucas's attempts at making Star Wars movies other than the original three (or, some would argue, the first two), and, in my opinion, the Wing Commander movie. More general examples would be how the author of any work, be it a work of fiction or a technical paper, is generally not a very good editor of that work (see: Stephen King). Engineers work in teams for a reason--the designer of something often misses its flaws.
The movie does hold it's own if you look at it from the view of a sci-fi enthousiast who has never played the games, read the novels, or saw the cartoon.
I don't know about "sci-f enthusiasts", but the movie was not well received by the general public. Just 9% fresh with an average rating of 2.8 out of 10 on Rotten Tomatoes. Granted, that's critics, who often take a dim view of science fiction (although not always...Serenity sits at 81% with an average rating of 7.2), but movies that came out a while back often have artificially inflated ratings on Rotten Tomatoes, because they only people that review movies that far back are fans of the movies. IMDB rates it a 3.7 out of 10, and that IS sci-fi enthusiasts, or at least people who were enthusiastic enough to see a low-budget sci-fi movie that didn't have a huge publicity machine behind it. Again, IMDB often inflates movie ratings because the only people that bother to rate it are people that care about it.
I'm not one of the movie's huge detractors (I actually thought the acting was very very good, even Lilliard's, with the glaring exception of Freddie Prinze Jr.), but I wouldn't call it a "good" movie, and it seems not many other people do either.
If you're going to talk about people that never played the games, never read the novels, or saw the cartoon, you're almost by definition talking about people that don't know all of LOAF's trivia about how the movie was re-edited at the last minute (i.e. Merlin), how the buget shortfalls forced them to do things they wouldn't have chosen to do, how the scripts were changed...etc. You probably also don't know that Roberts was intentionally trying for an underwater "Run silent run deep" feel. So what you see is just a fairly bad low budget sci-fi flick with bad acting by the lead actor, plot holes big enough to drive a Mack truck through, bad physics and astronomy, and some pretty special effects that look fairly pedestrian by today's standards.