I don't trust them. They go apeshit overboard positively and negatively. I've glanced through the first page. That guy sounds like he needs to get a life and a girlfriend. Geez. Even though he says he recognizes that film is a different medium I don't think he really grasps that most of Adams wordiness won't translate well to the big screen nor can everything fit for time. Compromises have to be made. Not knowing what the ending entails, maybe they're saving stuff for a sequel or two.
I'll likely revisit that page after I see the movie to see what he nitpicks. I'd find it quite amusing if most of the screenplay that Adams wrote was preserved.
This isn't unlike the Red Dwarf novels and the TV series. I read the first two novels ahead of seeing the TV series. I was slightly disappointed that the whole bit up to Lister getting aboard Red Dwarf was skipped in the TV show. Plus there was the change in his motivations for bringing his cat Frankenstein onboard. Depending on what they do, origin or TV continuation, I expect compromises for the movie too.
Another childhood favourite is in the works, Transformers, which already has been announced that it won't be entirely faithful to the old G1 cartoon and comics. Megatron will be a tank, Soundwave not a cassette recorder and others modified from their original forms and characters. A lot of fanboys are going apeshit over that on the producers website. Sad. I will be slightly annoyed if Cullen and Welker don't reprise their voice roles but not kicking, screaming and sulking in the corner like most fanboys.