Marvin is NOT CGI (He may be CG'd in some situations, but...) That's Warwick Davis in a suit!

"The new movie does NOT fulfill the Douglas Adams vision"
I'll wager it fulfills Adams vision for THIS movie....   Remember, he did write most of the screen play for this film...   And I seem to recall hims saying something about what he was doing in "Salmon Of Doubt"... about how 'die hard fans' of the book or radio or BBC TV version were probably NOT gonna like what he was doing this time around, and that he really didn't care.

But I'm not gonna defend it too strongly... I haven't seen it... yet.